CN117822564A

CN117822564A - Construction method of manual hole digging pile

Info

Publication number: CN117822564A
Application number: CN202311669455.8A
Authority: CN
Inventors: 黄哲隽; 李盼盼; 徐博; 伯睿飞; 刘根深; 张�浩; 郑凡; 赵世伟; 梁诗晗
Original assignee: CCCC First Highway Engineering Co Ltd; Fourth Engineering Co Ltd of CCCC First Highway Engineering Co Ltd
Current assignee: CCCC First Highway Engineering Co Ltd; Fourth Engineering Co Ltd of CCCC First Highway Engineering Co Ltd
Priority date: 2023-12-06
Filing date: 2023-12-06
Publication date: 2024-04-05

Abstract

The invention provides a construction method of a manual hole digging pile, which belongs to the technical field of hole pile construction, and comprises the steps of pile position positioning measurement, locking construction, hole opening arrangement, pile hole excavation, slag discharge transportation, final hole detection, steel bar engineering construction, pile foundation concrete pouring, pile head breaking and pile foundation detection. The invention greatly improves the whole construction progress through the rapid construction of the steel bars, and meanwhile, the automatic steel bar welding of the construction running water ensures the welding quality of the steel bars and the engineering quality of the pile steel bars, and the rapid excavation mode of the movable bottom bucket is used in the construction of excavation, thereby accelerating the excavation progress, and the automatic detection of the pile body is used, so that the construction quality is better ensured.

Description

Construction method of manual hole digging pile

Technical Field

The invention relates to the technical field of hole pile construction, in particular to a manual hole digging pile construction method.

Background

The common manual hole digging pile is one of the common foundation types in mountainous areas and hilly areas. The foundation belongs to an undisturbed soil foundation, is not excavated greatly, but is supported by a concrete retaining wall, is manually excavated to the designed burial depth, and finally forms a foundation geometric dimension model by using a soil substitution model, and is formed by pouring concrete under a reinforcement cage. The upper soil resistance of the manual hole digging pile of the undisturbed soil foundation is small, the manual hole digging pile is easy to be interfered by horizontal force, and a large bending moment is generated, so that the upper part of the manual hole digging pile is greatly displaced. For this reason, the diameter and the burial depth of the manual hole digging pile have to be increased to improve the fixing ability of the foundation to the manual hole digging pile, thereby reducing the displacement of the upper portion of the manual hole digging pile. The existing manual hole digging pile is low in efficiency and low in speed, so that a manual hole digging pile construction method with higher efficiency and higher speed is needed to be designed.

Disclosure of Invention

The invention aims to provide a manual hole digging pile construction method, which solves the technical problems that the existing manual hole digging pile is low in efficiency and speed and affects the construction period of a construction site.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

the construction method of the manual hole digging pile comprises pile position positioning measurement and locking construction, orifice arrangement, pile hole excavation, slag discharging transportation, final hole detection, steel bar engineering construction, pile foundation concrete pouring, pile head breaking and pile foundation detection to finish construction.

Further, the concrete process of pile position positioning measurement and locking construction is as follows:

(1) Writing a coordinate calculation program according to a design drawing, rechecking each designed pile foundation coordinate, ensuring that the coordinate is correct, measuring the original ground elevation at the pile foundation position before the equipment enters the field after construction control encryption is finished, finishing the data, firstly coarsely laying coordinate points during pile foundation construction lofting, driving the pile piles into the field by using 5cm multiplied by 30cm wood piles, accurately lofting the coordinate points on the wood piles after the wood piles are firmly driven, marking the coordinate points by iron nails or red paint, measuring the actual coordinates of the marked lofting points after lofting is finished, comparing the actual coordinates with the design coordinates, and conforming to the design specification requirements to lofting the next point;

(2) According to the accurate position after measuring and positioning, after leveling and cleaning a construction site, adopting a C30 reinforced concrete locking notch, wherein the thickness of the locking notch is 30cm, the width of the locking notch is equal to the design diameter of a pile plus 0.6m, the locking notch is 30cm higher than the ground, a drainage ditch is dug at the outer side of the locking notch, sundries at an orifice are prevented from falling into the orifice to hurt people and the surface water flows into the orifice, mortar is used for hardening in the range of 0.6m around the orifice, an assembled safety guard fence is required to be arranged around the orifice, the height is not lower than 1.2m, a pile protector is arranged at the top of the locking notch in a horse-riding pile mode, the crossed plumb line of the pile protector is overlapped with the center plumb line of the pile, the deviation of the center position of the pile is ensured not to exceed the allowable error specified in the specification, namely, the pile group is not more than 100mm, the single row of piles is not more than 50mm, and after the inspection and approval is carried out;

the pile protector is made of steel bar heads of main steel bars of the steel bar cage, and steel bars are inserted into the locking openings for 20cm and exposed for 10-15 cm, so that the pile protector is used as a pile protector fixing rod and a locking opening embedded part for fixing the steel bar cage.

Further, the concrete process of slag discharging and transporting is as follows: the manual hole bottom slag loading is adopted for hole digging and slag discharging, the winch lifts the hole discharging mode to slag, the lifting speed of the winch is 0.3 m/s-0.5 m/s, the ground pushes out the open land beyond the range of the pile hole edge 3m by using the trolley, the waste soil height is not more than 1m, the hole digging waste materials are orderly and normal to be piled up and transported to a waste soil field in time, and the waste soil cannot be discarded in the red line range or outside the red line range at will.

Further, the specific process of the end hole detection is as follows:

in the process of excavation, the axes, the aperture and the gradient of the hole site are inspected at any time, the situation that the deviation and the aperture of the pile hole exceed the specifications is found to be corrected in time, a construction record is made during inspection, a quality record is made during construction, the construction progress and the geological change condition are mastered, a design unit is timely reported when the actual geological condition and the geological report of the site come in and go out is found, and meanwhile, the original data accumulation is made for completion inspection;

hole bottom treatment is carried out after the hole is dug to the design depth, so that a soft layer without loose slag, silt and sediment is leveled, whether pile forming hole positions, hole diameters, pile top and pile bottom elevation, pile body verticality, virtual soil thickness, rock embedding depth and pile bottom ponding penetration conditions meet design requirements or not is checked, hole bottom inspection is carried out, and image data are reserved;

detecting the pile diameter by adopting a hole detector with the diameter equal to the designed pile diameter and the length of 4 times of the pile diameter after hole forming;

the single pile end is embedded into breeze rock stratum not less than 3D, stroke rock stratum not less than 5D, rock saturation uniaxial compression strength standard value is more than 15MPa, the pile diameter range below the pile end is not less than 3 m, no soft interlayer, fracture breaking belt and cave distribution exist, no rock body empty face exists in the pile bottom stress diffusion range, the hole bottom inspection is carried out in a drill rod or geophysical prospecting mode, 5 holes are arranged at the hole bottom in a quincuncial shape, and the hole depth is 5m.

Further, the concrete process of the steel bar engineering construction is as follows:

the pile foundation reinforcement cage is intensively processed in a reinforcement processing field, and the flat car is transported to the field, so that the construction technology of integral hoisting of the automobile crane is adopted.

Further, the concrete pouring process of the pile foundation concrete is as follows:

5.1, arranging a blanking hopper, a stringing barrel or a guide pipe:

i-steel is used for manufacturing a groined type movable support frame, the support frame is placed at the center of an orifice before pouring, a sleeper is arranged under the support frame in a cushioning mode, an automobile crane lifts a hopper away from the ground fixed position, a first section of blanking string barrel is hung, a crane is gradually lifted to complete the installation of all string barrels, then the automobile crane transfers the whole string barrels to a construction hole site, the lower hook is fixed on the support frame until the hopper is firmly fixed on the support frame, and a nylon rope is used for firmly hanging the middle of the string barrels to prevent falling and hurting people;

5.2, pouring pile body concrete, wherein the concrete process is as follows:

1. the concrete mixing proportion, the preparation materials, the reinforcing steel bars and the like are checked to be qualified by quality inspection engineers and test inspectors, and can be used after approval by a supervision engineer, and the concrete mixing proportion is formulated according to a pouring mode;

2. the concrete is mixed intensively, automatically metered and transported in a tank truck, the casting mold temperature of the concrete is not lower than +5 ℃ and not higher than +30 ℃, otherwise, corresponding measures approved by a supervision engineer are adopted. When pouring is performed by adopting a tube stringing method, two vibrating workers in each hole perform vibrating operation by adopting a 50-type inserted vibrating rod; when pouring is performed by adopting a conduit method, the slump test is carried out on the concrete on the construction site according to the requirement of pouring underwater concrete, and the slump is controlled between 16 cm and 22 cm;

3. The concrete pouring is performed, the dry pile is mainly used for the concrete pouring of the manual hole digging pile, but the situation that the hole wall water seepage is large, the hole bottom is close to or exceeds an underground water line is caused, the pile body is defective or even broken, the water seepage of the pile hole is measured before the concrete is poured, when the water seepage is larger than 6mm/min, the pile is poured according to the underwater pouring pile, and when the water seepage is smaller than 6mm/min, the pile is poured according to the common concrete pile;

when the concrete is dumped, the free falling height is not more than 2 meters and is not isolated, and when the falling height is more than 2 meters, the concrete falls through facilities such as a string tube, a chute, a conduit and the like;

(1) Pile body concrete pouring of pile foundation with pile length below 20m and no ponding adopts a tandem method for construction:

the method comprises the steps of conveying concrete from a mixing station to a hopper of an orifice by a tank truck, then leading the concrete into the bottom of the orifice by a string cylinder, arranging 2 vibrating workers under the well, respectively operating 1 vibrating rod of 50 types, controlling the layering thickness of the concrete at 30cm, stopping discharging before starting vibrating after finishing distributing, stopping sinking the concrete during vibrating, avoiding bubbling, enabling the surface to be flat and slurry-flooding until the surface is flat, increasing along with the concrete surface during pouring, synchronously removing the string cylinders section by section, ensuring the distance from the bottom of the string cylinder to the cast-in-place concrete surface to be within 2m, selecting the superpouring of 50cm for avoiding the influence of top slurry, and smoothing the concrete at the pile top before initial setting of the concrete, thereby avoiding plastic shrinkage cracks or circumferential shrinkage cracks;

(2) When the pile length is more than 20m or ponding exists in the hole and the water cannot be discharged, the pile body concrete is poured according to the requirement of pouring underwater concrete by adopting a conduit method;

(1) first concrete pouring, wherein the first concrete pouring adopts a ball pulling method for construction:

the distance from the bottom opening of the guide pipe to the bottom end of the pile hole is controlled to be 0.4m, the quantity of first poured concrete can meet the requirement that the first embedding depth of the guide pipe is more than 1.0m, 1m is taken, and the quantity of the concrete is calculated by adopting the following formula:

v-quantity required for pouring first concrete (m ³ )；

D-pile hole diameter (m);

H ₁ the distance from the bottom of the pile hole to the bottom end of the guide pipe is generally 0.3-0.4 m;

H ₂ -primary depth of embedding (m) of the catheter;

d-inner diameter of the catheter (m);

h ₁ the concrete in the pile hole reaches the embedding depth H ₂ When the concrete column in the conduit balances the height (m) required by the slurry pressure outside the conduit;

h ₁ ＝H _W ·γ _W /γ _c 。

wherein:

H _w -height of free surface of slurry to top surface of concrete (m)

γ _w -mud weight (g/cm 3);

γ _c -concrete weight (g/cm 3);

the mud density is 1.1g/cm3, the concrete density is 2.4g/cm3, the inner diameter of the guide pipe is 350mm, the height of the mud surface of the underwater pile is up to 8.0m, the predicted value is obtained here, the mud in the pile is not filled in the pile hole, and the calculated value is as follows:

D＝1.5m：V＝2.8m ³ ；

D＝1.6m：V＝3.2m ³ ；

D＝1.8m：V＝3.9m ³ ；

D＝2.0m：V＝4.7m ³ ；

D＝2.2m：V＝5.7m ³ ；

D＝2.5m：V＝7.2m ³ 。

the capacity of the storage hopper is 1-1.5 m ³ In order to ensure the continuity of the first concrete pouring, a steel plate is adopted to manufacture a cake with the outer diameter larger than the inner diameter of the guide pipe, a steel wire rope is used for hanging the cake to be used as a ball pulling device, the ball is pulled when the hopper is full of concrete, the concrete is poured into the pile bottom from the hopper, meanwhile, the concrete is kept continuously poured into the hopper, the continuity of the concrete pouring is realized, and the capacity of a concrete tank truck is 8m ³ Or the model is provided with 1 pump truck and one 25 ton truck crane at the same time to ensure that the first batch of concrete is poured smoothly, and measuring the elevation of the concrete surface by adopting a measuring rope after the first batch of concrete is poured;

(2) continuous casting of concrete, after the first batch of concrete is successfully cast, continuous casting is carried out until casting of the whole pile is completed, the pile position adjacent to the pile cannot be operated before the concrete is finally set, and a guide pipe is lifted and removed by adopting a 25t automobile crane;

in the pouring process, the water head height in the hole is kept, the embedding depth of the guide pipe is controlled to be 2-6 m, the position of the concrete surface in the pile hole is detected at any time, the embedding depth of the guide pipe is adjusted in time, and the embedding depth of the guide pipe is properly widened according to the actual condition of the site on the premise of ensuring that the guide pipe can be lifted smoothly, but the maximum embedding depth is not more than 9 m;

in order to ensure that the reinforcement cage does not float upwards, when the top surface of the poured concrete is 1m below the bottom of the reinforcement cage, the pouring speed is reduced, when the top surface of the concrete rises to more than 4m above the bottom of the cage, the guide pipe is lifted, and the normal pouring speed is restored after the bottom opening of the guide pipe is higher than the bottom of the cage by more than 2 m;

detecting the slump of concrete in real time, sampling and manufacturing a concrete test piece according to the standard requirement to test the quality of pile foundation concrete, particularly paying attention to the firm bolting when the conduit is removed, and ensuring that the occurrence of a pipe dropping event is avoided;

When pouring is nearly finished, checking the pouring quantity of concrete, determining whether the pouring height of the concrete is correct, wherein the pile top Gao Chengying of the poured pile is higher than the designed elevation by not less than 0.5m, when the conditions of poor geological conditions, overlarge slurry density in holes, large pile diameter and the like exist, the overlarge height of the overlarge pile should be properly increased, the superfluous part of the overlarge pile should be chiseled before the construction of a bearing platform or before pile extension, the pile head after chiseled should be compact and have no loose layer, and the concrete should reach the strength grade specified by the design;

in the pouring process, appointed special persons are responsible for filling in underwater concrete pouring records;

(3) When the concrete is poured to the karst cave position, on the premise of not influencing the continuous pouring of the concrete, the continuity of the pile body concrete is guaranteed, the concrete pouring rate is reduced, the concrete is vibrated slowly, and the phenomenon that the retaining wall collapses to the cavity side of the karst cave due to too fast concrete pouring is avoided;

(4) And the pile body concrete is cast and formed at one time.

Further, the concrete process of pile head breaking is as follows:

pile head ring cutting integral breaking technology is adopted in pile head breaking construction, and the construction process flow is divided into 7 steps:

the first step: cleaning the earthwork of a foundation pit, measuring the elevation of the pile top, and arranging a cutting line with the width of 15cm at the position of the pile top, wherein a red paint mark is adopted;

And a second step of: and (5) circular cutting by a cutting machine to obtain the steel bars. The subsequent air pick operation is convenient, and the reinforcement protection layer is not damaged;

and a third step of: peeling the outer protective layer of the reinforcing steel bar on the upper side of the notch by the pneumatic pick;

fourth step: the steel bar is slightly bent outwards, so that the construction is convenient;

fifth step: adding a drill to break, wherein the drill bit is horizontal or slightly upward, and the position is 15cm above the pile top line;

sixth step: the pile head concrete breaking whole is lifted by a crane, the pile head and the pile body are ensured to be completely separated before lifting, then lifting is carried out, the pile head concrete breaking whole is lifted as slowly as possible to avoid damaging the steel bars during lifting, and the operator should be far away from the operation range during lifting so as to prevent accidents caused by falling of the pile head. The pile head is lifted out and then placed at a place far away from the foundation pit;

seventh step: after the pile head is lifted, part of the fracture surface is rugged, manual chiseling is not needed, redundant parts are chiseled according to the designed elevation, and the fresh concrete surface of the pile top is exposed.

Further, the concrete process of pile foundation detection is as follows:

after pile forming, nondestructive inspection is carried out one by one, and a sound measuring pipe is installed on each pile according to the design requirement by adopting a sound measuring method so as to check the integrity of the pile body by adopting an ultrasonic detecting method, and before pile foundation detection, field construction technicians should check whether the sound measuring pipe is blocked or not, take effective measures to dredge the sound measuring pipe and fill clear water in advance.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

the invention greatly improves the whole construction progress through the rapid construction of the steel bars, and meanwhile, the automatic steel bar welding of the construction running water ensures the welding quality of the steel bars and the engineering quality of the pile steel bars, and the rapid excavation mode of the movable bottom bucket is used in the construction of excavation, thereby accelerating the excavation progress, and the automatic detection of the pile body is used, so that the construction quality is better ensured.

Drawings

FIG. 1 is a flow chart of the method of the present invention;

FIG. 2 is a schematic view of pile hole digging according to the present invention;

FIG. 3 is a schematic view of the blast safety shield of the present invention;

FIG. 4 is a flow chart of the water mill drilling construction process of the invention;

fig. 5 is a process diagram of the reinforcement welding construction of the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described in detail below by referring to the accompanying drawings and by illustrating preferred embodiments. It should be noted, however, that many of the details set forth in the description are merely provided to provide a thorough understanding of one or more aspects of the invention, and that these aspects of the invention may be practiced without these specific details.

As shown in fig. 1, the construction method of the manual hole digging pile comprises pile position positioning measurement and locking construction, hole opening arrangement, pile hole excavation, slag discharge transportation, final hole detection, steel bar engineering construction, pile foundation concrete pouring, pile head breaking and pile foundation detection.

The detailed manual hole digging pile construction process mainly comprises the following steps: measuring lofting and pile positioning, excavating first pile hole earthwork, pouring orifice guard rings, detecting pile foundation center positions, placing additional reinforcing steel bars and supporting wall templates, pouring first pile wall concrete, installing a transportation frame, installing an electric hoist (a winch), installing a movable bottom bucket, illuminating lamps, ventilators, water pumps and the like, excavating and lifting second pile hole earthwork, placing additional reinforcing steel bars and supporting wall templates, detecting pile foundation center positions, pouring second pile wall concrete, sequentially carrying out downward circulation operation, excavating and expanding bottom earthwork, checking and accepting pile holes, processing and installing a reinforcement cage, installing a concrete conduit or a string barrel, pouring underwater or common concrete, detecting and accepting pile foundation finished products.

The concrete process of pile position positioning measurement and locking construction is as follows:

The specific process of the orifice arrangement is as follows:

1. the orifice is enclosed and protected, and the specific process is that

(1) Before digging, firstly making protection work of an orifice, arranging a circle of protection fence on the orifice, wherein the height of the fence is not lower than 1.2m, and one surface of the fence is made to be movably arranged and used as a slag discharging channel, and hanging a safety warning board and a pile foundation parameter board on the fence;

(2) The orifice is provided with a special guard, and meanwhile, a dense mesh steel bar net cover plate is arranged for protection, and each edge of the steel bar net cover plate exceeds the edge of the orifice by 0.3m;

(3) When the operation is stopped, the orifice is covered with a locking port enclosure, and a warning signboard is arranged to prevent personnel from falling into the orifice;

(4) Digging drainage ditches around the orifice to prevent surface water from flowing into the well;

(5) Taking attention to the trend of the unearthed road, the dug waste soil needs to be transported in time, and the waste soil and sundries cannot be accumulated within a range of 3m away from the periphery of the orifice, so that any vehicle is prohibited to run within 3m of the pile hole edge;

2. the lifting frame is arranged as shown in fig. 2, and the specific process is as follows:

an electric hoisting machine is adopted, a field technician checks and accepts the hoisting frame before construction after entering a field, the hoisting frame comprises relevant information of a product use instruction and a qualification certificate, deformation and corrosion conditions of the hoisting frame are checked, whether installation of bolts and bolts meets safety requirements or not is checked, the model and specification of a lifting rope, a lifting hook, an electric hoist or a hoisting machine meet the requirements of a special construction scheme, the lifting rope meets the requirements of normal use and safety assurance, and a winding drum is provided with an automatic clamping safety device or a steel wire rope anti-falling device;

when the pile is installed, the centers of the bucket and the thick rope are consistent with the center line of the pile hole, so that the center line is roughly controlled when the pile is dug, when the pile is dug in, the center of the circle is found by a ruler rod, and the depth of the hole is measured by a datum point on the ground, so that the pile position, the perpendicularity and the section size are correct;

Before installing the lifting frame, firstly calculating the balance weight of the frame and checking the strength of the steel wire rope;

the diameter of a bucket at the construction site of the hole digging pile is 0.4m, the height of the bucket is 0.5m, a 6 x 7+FC-8mm steel wire rope is adopted, the nominal tensile strength is 1770Mpa, and the breaking force of the steel wire rope is 37.6KN;

weight calculation:

the bucket is considered according to the most adverse condition, the suspended object is assumed to be granite, and the density rho=3000 kg/m ³ The capacity of the bucket under normal construction conditions must not exceed 100kg;

full weight of bucket:

g=mg=ρvg=3000×3.14×0.2×0.2×0.5×10= 1884.96 n=188.5 Kg, the weight of the bucket is 15Kg, the total weight m ₃ ＝203.5Kg；

m ₁ Is a tail counterweight, m ₂ For the middle counterweight, in order to ensure that the crane does not topple, the following conditions must be met at the same time:

①0.2m ₂ +1.25m ₁ >2.0×m ₃ the crane is prevented from overturning into the hole when being fully loaded, and the safety coefficient of 2 times is considered;

②0.8m ₂ >0.25m ₁ the crane is prevented from overturning outwards of the hole when the bucket is empty;

namely: 1.25m ₁ +0.2m ₂ >407；

0.25m ₁ -0.8m ₂ <0；

Assuming that no load and full load are just balanced, it is possible to: m is m ₁ ＝310kg、m ₂ ＝97kg；

m ₁ 、m ₂ The larger the elevator is, the more stable the elevator is at full load, m ₂ The larger the elevator is, the more stable the elevator is in no-load, and the stability of the elevator is comprehensively consideredTaking m as a rotation difficulty factor of the elevator when the counterweight is overweight ₁ 310kg, m ₂ 100kg;

1.25m ₁ +0.2m ₂ ＝407.5>2×203.5=407, satisfying the condition

0.25m ₁ -0.8m ₂ ＝-2.5<0, satisfy the condition

Therefore, the tail counterweight 310kg and the middle counterweight 100kg of the helicopter can be ensured to be stable in other running processes and ensure safety;

checking and calculating a steel wire rope:

breaking force S=37.6KN of 6 x 7+FC-8mm steel wire rope, when the steel wire rope is used as a sling, the safety factor is 6-7, and the allowable tension P=37.6/7=5.4KN > m of the steel wire rope at the construction site ₃ =2.0 KN, meeting the requirements;

the on-site construction counterweight adopts a C20 concrete precast block, and a reinforcing steel mesh is required to be placed in the precast block, so that the overall stability of the precast block is improved, the counterweight stacking is required to be smooth, the stacking blocks above the bottom layer are not suspended, whether the precast block is complete or not is checked on time, and the precast block is damaged and replaced in time;

after the lifting frame is installed, before and during the construction period, checking whether the wheels, the shaft, the bracket, the lifting rope, the hook, the safety device, the lifting bucket and equipment and tools for braking of the lifting machine are intact, whether the protective measures are safe in place and correct and firm and available, checking the intact condition of vertical transportation equipment at any time in construction, whether three steel wire rope clamps are arranged, whether the diameter of the steel wire rope meets the standard and standard requirements, whether the abrasion of the steel wire rope exceeds the standard, the operation of the lifting machine with diseases is forbidden, and the slipping of the steel wire rope is forbidden;

3. The ventilation equipment is installed by the following specific processes:

when the hole depth reaches 10m, the natural flow condition of the air at the bottom of the hole is worsened, and CO in the air ₂ The content gradually accumulates, when the content reaches 3%, the respiratory system of people is disturbed, headache and vomit symptoms are generated, mechanical ventilation is adopted when the digging depth reaches 10m, the model of the ventilator is determined according to the hole depth, the hole diameter and the air condition in the hole, the air in the hole is ensured to be fresh, and the work efficiency is ensured1 ventilator is configured on each pile foundation of each hole, the ventilation pipe is fixed outside the hole, the ventilation pipe is connected and fastened with the ventilator, the bottom opening of the ventilation pipe is 2m away from the bottom of the excavated hole, a T35 type shaft ventilation fan is selected, and the ventilation quantity can reach 800m ³ And/or more.

4. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of pile hole excavation is as follows:

2.1 pile body excavation

(1) Before pile hole excavation construction, the pile distance needs to be considered, two adjacent pile holes cannot be excavated simultaneously in construction, and staggered skip excavation at intervals is preferred. Pile foundation of one side of the pile site with steep topography is firstly excavated to be convenient for slag tapping, and each construction site is inspected on site before construction, and manual danger is cleared, and the slope is protected according to the design.

(2) The pile hole is excavated when being in different stratum as follows:

(1) the softer soil body at the upper part of the pile foundation is manually carried out layer by layer from top to bottom by using picks and shovels, the soil body is crushed by using a pneumatic pick when meeting the hard soil layer, and the excavating sequence is that the middle part is firstly excavated and then the periphery is excavated.

(2) The method for excavating the strongly weathered rock stratum comprises the following steps: the core is most broken stone, a small amount of sand and soil, broken stone is easy to crush, an air pick is adopted for excavation, and the electric air compressor supplies compressed air.

(3) The excavation method of the slightly weathered rock stratum and the weakly weathered rock stratum comprises the following steps: when the stratum is secondary stone and stone is required to be blasted, shallow hole loosening blasting is adopted, the explosive consumption is controlled, supporting is reinforced near the blasthole, detonating ropes or electronic detonators are required to be adopted for detonating the hole depth of more than 5m, and air pick is adopted for excavating to the hole bottom in the range of 30cm at last, so that disturbance to a substrate is prevented, and the bearing capacity of the substrate is influenced.

(3) After each section of pile hole is excavated, checking the aperture, verticality and center deviation, checking whether the center of the hole position is on the same vertical line with the center of the pile, and checking whether the hole position and the aperture of each layer meet the requirements. And when the depth of each digging is 0.5-1.0 m, the concrete wall is poured by the vertical mould in time, and the concrete wall cannot be stopped during the period, so that the hole collapse is prevented.

(4) And (3) in the hole digging process, an on-site engineer makes an original record, and if the geological condition of the rock stratum is found to be obviously different from the description of the design drawing, the original record is timely reported to a supervision engineer, a design and a general supervision. The next job must not be performed until approval by the supervision engineer.

(5) In order to prevent the hole slag from overflowing out of the bucket or the bucket from being separated from the lifting hook in the vertical lifting process of the hole slag, the safety of underground operators is ensured when spoil and other building materials are vertically transported in a well, and a safety zone is arranged at the bottom of the well. When the hole is dug to below 5m, a semicircular protection plate is arranged on the protection wall at the position of about 3m on the bottom surface of the hole, the protection plate is firmly fixed, and the protection plate can be made of a steel plate or a dense-eye reinforcing steel bar net. When the materials and earthwork in the hole are lifted out of the hole, hole bottom personnel should stop the hole digging operation and hide in a safety area, and construction is performed after the lifting is finished, so that the objects are prevented from falling to hurt people in the lifting process. Meanwhile, a safety rope and a soft cat ladder used when the hole is erected in the hole and the pile hole is extended to the working surface along with the depth of the pile hole. The width of the climbing ladder is preferably 0.5m, the step pitch is preferably 0.3m, and the bearing capacity is not less than 2KN.

(6) In the electric lifting process, the performance (limit and the like) of the lifting machine, a steel wire rope for lifting, a loop back hook, soil loading equipment and the like are frequently checked, and the equipment with potential safety hazards is replaced in time.

(7) The lifting equipment must have a limiter and an anti-drop safety device, the lifting frame is stably and firmly installed, the counterweight is not less than the design requirement, a precast block is necessary to be adopted for counterweight, the capacity of the lifting bucket must not exceed 100kg, the earth and stone contained in the lifting bucket must be lower than 15-20 cm of the bucket mouth, and the lifting bucket is covered, and the lifting is not required to be increased at will without calculation or approval of field technicians, so that manual lifting is forbidden; the lifting device and the electricity should be checked every time a shift is taken. The waste soil is loaded into the bucket and transported vertically, and a lifting hanger is arranged at the upper opening of each pile hole and lifted by a 0.5T winch.

2.2 blasting modes and scheme selections

The blasting operation of the hole digging pile is mainly to consider that the outer side, the bottom and the protecting wall of the hole digging pile are not damaged and keep the integrity of the hole digging pile, so that the hole digging pile is designed and constructed by adopting a shallow hole loosening blasting method (blasting design calculation is carried out by a professional third party), and field operation is carried out by professional blasters.

1. The blast protection, as shown in figure 3,

the explosion is carried out underground, the purpose of safety protection can be achieved only by making protection of the orifice, the orifice is tightly covered, a layer of phi 12 reinforcing steel bar net is covered on the locking notch, then the shock pad is covered and the weight is pressed (sand bags are used for pressing the weight), and flying stones can be basically controlled in the well.

2. Preventive measures of blasting vibration, shock wave, dust and noise

(1) Explosion vibration prevention measure

(1) Controlling single-sound dosage and blasting scale;

(2) the method has the advantages that a good blasting free surface is created, a reasonable blasting circuit is designed, the ultra-deep is reasonably controlled, and the section is flush as much as possible;

(3) when the shallow hole is adopted to treat the root and open the free surface, the explosion of the kettle is forbidden so as to avoid the explosion vibration exceeding the standard caused by the centralized effect of the medicine room;

(4) the site survey work is enhanced, the blast holes are distributed uniformly as much as possible, and the local blast hole resistance line is prevented from being overlarge.

(2) Shock wave preventive measures

(1) Filling blasting is carried out, and naked blasting is forbidden;

(2) the blocking quality can be well controlled by strengthening;

(3) strictly controlling the minimum resistance line, wherein the blocking length is larger than the resistance line;

(4) when special weather conditions are to be blasted, care should be taken to prevent diffraction and reflection effects of air shock waves.

(3) Toxic and harmful gas preventive measures

Explosive explosion generally reaches zero oxygen balance or approaches zero oxygen balance, and explosion generally does not generate a large amount of toxic gas (but must be paid attention in actual explosion work). In order to avoid the harm of toxic gas generated in blasting to surrounding personnel, the following measures must be taken:

(1) ordering and using blasting equipment according to a construction progress plan, so as to avoid explosive property change caused by over-period storage;

(2) the explosive materials with qualified quality are used, and particularly the explosive materials meet the conditions of stable performance, zero oxygen balance and the like;

(3) filling all the blast holes;

(4) after blasting, the blasting machine should wait for more than 15 minutes, and after the blasting smoke escapes, the blasting machine can enter the site safety inspection.

(4) Dust prevention measures

(1) Proper pore network parameters are encrypted, standard charging measures are adopted, the working time of the explosive energy is prolonged, and a large amount of dust generated by excessively crushing the rock in the pore wall of the explosive is avoided;

(2) All the drilling holes are blocked and blasted, and water is sprayed before blasting under the condition of allowing conditions;

(3) the driller should keep wearing a mask when drilling, and implement wet drilling to avoid the lung disease caused by dust inhalation;

(5) Noise prevention measures

(1) Strictly forbidden to adopt naked blasting, and fully blocking the drilling blasting;

(2) the air compressor and other high noise equipment are preferably placed in a downwind area far away from the village civil house;

(3) the sufficient blocking length is ensured, and the gun is prevented from being punched;

(4) reasonable blasting time is arranged, and the Kong Waiyan detonator is properly wrapped when the initiating circuit is connected, so that the method is also an effective noise reduction method.

2.3 wall protection construction

(1) According to the technical specification of highway bridge construction (JTG/T3650-2020), a pile hole must be dug and a section of retaining wall is poured, the height of the retaining wall with better geology is generally 1m, and the risk operation of not pouring the retaining wall in time is strictly forbidden. For weak stratum, water and sand gushing stratum, the wall protecting section height can be reduced to 0.3-0.5 m. On the premise of ensuring the diameter of the pile hole, the concave-convex of the hole wall can not be treated, and the hole wall support can not occupy the diameter of the pile.

(2) According to the actual situation of the site, the wall is protected every 0.8-1.0m when the hole is dug. The wall protection concrete construction adopts self-made steel templates, each section of the templates is divided into 5-6 sections of circular arcs, the thickness of the panel is not less than 3mm, the back edge adopts arc L5 angle steel or [5 channel steel ], the templates are required to be smooth and flat so as to be beneficial to the connection with pile body concrete, and the deformed templates are trimmed in time, so that the wall protection size is ensured to be correct. In order to further improve the adhesion between the column body concrete and the retaining wall, and facilitate the concrete to enter the mould, the horn staggered-platform-shaped retaining wall is adopted. The overlapping length of the retaining wall is not less than 50mm, the thickness of the upper opening is 15cm, the thickness of the lower opening is 10cm, the structural characteristic of the retaining wall is that the outer side of the retaining wall is a cylinder with the same diameter, the inner side is a truncated cone, when the retaining wall is poured by a formwork, the strength of the concrete of the retaining wall is the same as that of the concrete of the pile body, and a gap of 5cm is reserved between the two sections of retaining walls, so that the pouring construction of the concrete is facilitated.

(3) Continuous wall protection is needed during hole digging, and the stable state of hole wall support is often checked. And when the strength of the upper section wall protecting concrete reaches the form removing strength, then the lower section is excavated. When the retaining wall is filled with concrete, the upper section and the lower section of the template are disassembled and are supported for turnover from top to bottom. The templates are connected by U-shaped clamps, two No. 8 channel steel rings are arranged up and down to tightly prop up, the steel rings are composed of two semi-circles, and are connected by bolts without additionally arranging supports, so that concrete pouring and lower section soil digging operations are facilitated.

(4) The first section of the retaining wall is dug downwards from the bedding surface by 0.7m, and each section is used as a construction cycle when being downwards constructed (namely, each section of soil is dug, and then one section of concrete retaining wall is poured). The concrete retaining wall and the hole digging well wall are firmly combined, and the retaining walls are mutually overlapped by 50mm. The reinforced concrete retaining wall is adopted, a plain round steel bar ring network with phi 10@200mm is adopted, phi 12 threaded steel bars are additionally implanted, and the retaining wall is arranged in a quincuncial manner at a distance of 40cm so as to prevent the retaining wall from sliding downwards.

(5) In order to ensure the perpendicularity of the pile, the center position and perpendicularity of the pile are corrected every time a section of retaining wall is poured.

(6) The retaining wall concrete is marked as C30, the same strength grade as pile foundation concrete (such as higher grade concrete when meeting special stratum) is adopted, the construction is strictly carried out according to the proportion approved by a test supervision engineer, the concentrated mixing is carried out at a mixing station, and the field mixing concrete is strictly forbidden.

(7) After mixing the concrete, transporting the concrete tank truck to a pouring site in time, wherein the pouring time does not exceed the initial setting time. And (3) hanging the concrete bucket to a retaining wall pouring point, wherein the retaining wall pouring point is provided with a special opening iron sheet chute, uniformly discharging and tamping the concrete along the periphery, and directly vibrating to be compact, thereby finishing pouring. After the irrigation is completed, the mould is removed and the strength is more than 5Mpa. The above sequence is cycled until the depth of the design requirement.

2.4 construction auxiliary measures

1. In-hole ventilation

(1) Before the hole digging personnel get down, the air in the hole is exhausted and replaced by a fan for 15min, and then a gas detector is used for detecting whether toxic and harmful gases exist in the hole, if necessary, small animals are put in for living examination, the observation time is not less than 15min, and the gas content measurement such as carbon dioxide is carried out, so that the air freshness of the working area at the bottom of the hole is ensured. If the CO2 content exceeds 3%, ventilation measures are adopted, and if the content does not exceed the specified standard, but the operator has breathing discomfort, ventilation or shift work and other measures should be increased.

(2) When the depth of the hole digging pile exceeds 10m, mechanical ventilation is adopted, the air volume is not less than 25L/s, the air pipe opening is required to be 2 meters away from the hole bottom, and the ventilation air volume is increased when the air pick is used for rock drilling, so that harmful gases are discharged.

(3) After each blasting, the ventilator is started to forcibly ventilate the hole for at least 15min, and toxic gas generated by blasting is discharged. And is equipped with a combustible gas/harmful gas detector and a gas mask.

2. In-hole illumination

The lighting in the hole is provided with a 36V low-voltage lighting lamp and an explosion-proof shield (if the underground environment is wet, 12V safety voltage is adopted), and the bulb is 2 meters away from the hole bottom and cannot be directly placed at the hole bottom.

3. Water-proof and drainage inside and outside hole

(1) The side of the hole pile and the water-proof and drainage in the hole pile must be made during the construction of the hole pile, and the water-intercepting and drainage ditch is built in a certain range on the Kong Zhuangding part ground to prevent rainwater from flowing back into the hole pile.

(2) When the underground water in the hole pile is small in water seepage, the mud water is lifted out by a bucket while digging soil; when a large amount of water seeps, a water collecting pit is dug in the hole, a certain amount of drainage hoses are reserved on the protecting wall, the water seeping from the hole wall is intensively drained into the water collecting pit, and then the high-lift submersible pump is used for draining the underground water out of the pile hole.

(3) For the safety of hole diggers, each water pump is provided with a leakage protector, and if abnormal, the water pump automatically trips.

2.5 special case handling

1. Conditions of karst cave in the process of excavation

(1) Notice matters

1) Before construction, detailed engineering geological survey reports are carefully checked, mileage stake marks are compared, and whether karst cave exists in each stake position, the position of the karst cave, the size of the karst cave and other data are known.

2) In the construction process, when the digging depth is close to the karst cave position shown in the geological survey report, the digging speed is reduced, and small-area tentative digging is performed to find out the karst cave.

3) Immediately after the karst cave position is determined, a treatment measure is taken, a constructor needs to tie a safety belt between waists, one end of a safety rope is connected through a safety bolt, the other end of the safety rope is connected to an orifice embedded part, and a special command is set during construction to keep in touch with the constructor at any time.

4) Two situations of encountering karst cave

(1) And (5) punching part of karst cave top plates in the manual excavation process, and finding karst cave cavities.

(2) In the blasting process, the karst cave top plate is directly blasted, and the whole karst cave cavity is revealed.

5) Site report after karst cave discovery

And immediately stopping the operation by the construction operator, transferring to a safe area, and reporting to field technicians. After checking karst cave scale and development condition, field technicians report to field responsible person, project technical department and technical responsible person respectively, and inform supervision engineer to field review.

(2) Karst cave type

(1) Soil hole: filling the karst cave without the filler dry cave and the fluid slurry (or accumulated water);

(2) karst cave in rock formations: half rock and half soil open karst cave and closed karst cave;

(3) beaded karst cave.

(3) Soil hole treatment

Namely, the karst cave is formed by the erosion of the soil body by the groundwater, and the karst cave is free of rocks, and can be filled with fluid slurry or hollow without filler. Under the condition of no external force stirring, the karst cave wall is generally in a stable state, so that stirring of the karst cave wall is avoided as much as possible when the karst cave in the soil is encountered, and construction by a blasting method is not suitable. When the soil body is to be penetrated through the karst cave, the construction is carried out by adopting a method of manually removing fillers in the karst cave and backfilling dense materials.

1) Dry hole without filler

(1) The condition in the karst cave can be directly observed after the filling-free dry cave is drilled through the top soil layer of the cave.

When the lateral depth of the karst cave is less than or equal to 1m and the wall of the karst cave is not collapsed, removing the impurities of the floating soil in the karst cave, and rapidly building rubbles (grout or dry yards), and reserving the thickness of the retaining wall during building. And constructing the reinforced concrete retaining wall after the karst cave treatment is completed.

(2) When the side depth of the karst cave is more than 1m and less than or equal to 3m, loose wood is selected to support the soil body on the top of the karst cave (disposable use, no removal) so as to ensure construction safety. After the cave roof is supported, cleaning the periphery of the karst cave, rapidly building rubbles (grout or dry yards), reserving the thickness of the retaining wall during building, binding reinforcing steel bars of the retaining wall, and installing a retaining wall template to pour concrete. The retaining wall height should be reduced to 50 cm/section.

2) The fluid slurry (or accumulated water) fills the karst cave.

Because the situation in the karst cave cannot be directly observed after the roof of the karst cave is drilled, the lateral direction and the height of the karst cave can be determined according to local conditions by using steel drills.

(1) When the side depth of the karst cave is smaller than 1m, the construction is performed according to the method of filling-free operation in the karst cave.

(2) When the side depth of the karst cave is more than 1m and less than or equal to 3m, supporting and reinforcing soil body at the top of the karst cave, pumping out fluid slurry or accumulated water in the karst cave, rapidly building rubble (slurry building or dry stacking), and reserving the thickness of a retaining wall during building. And constructing the reinforced concrete retaining wall after the karst cave treatment is completed. The retaining wall height should be reduced to 50 cm/section.

3) When the karst cave height is less than 1.0m, the retaining wall can be poured to the bottom at one time. When the karst cave height is more than 1.0m, the construction should be carried out in sections (each section height does not exceed 0.5 m), and the construction of the next section should be carried out after the concrete strength of the previous section reaches 2.5 MPa. When the side depth of the karst cave exceeds 3.0m, the plane trend of the karst cave is ascertained by using steel drills, the plane graph of the bridge is marked clearly, and the construction unit tissue design unit treatment is submitted.

(4) Karst cave in rock layer

The karst cave in the rock layer is generally provided with an open karst cave (fluid bowl, funnel), a closed karst cave and the like, and the open karst cave is provided with half rock and half soil or a radial fluid bowl and the like. The karst cave may be filled with hard clay, soft soil, fluid slurry, water supply, etc. or may be filled with dry cave.

1) Half rock and half soil open karst cave

(1) When the soil body is hard clay, the construction is carried out downwards in a section-by-section depth of 1.0m, the soil body part is firstly hollowed, then the rock is blasted to clear out the stone slag, the retaining wall steel bars are installed after the pile holes are corrected, and the retaining wall concrete is poured until the karst cave layer is penetrated.

(2) When the soil body is soft soil (but does not flow), constructing downwards in a section-by-section 0.5m depth, firstly obliquely driving hard logs (tip diameter is 3-5 cm, pitch is 15 cm) with the length of 1.0-1.5 m outside the circumferential hole of the hole wall in the soil body part, then hollowing out the soil body part, manually chiseling out the rock body part, installing wall protection steel bars after correcting the hole wall, and pouring wall protection concrete until penetrating through a karst cave layer.

(3) When the soil body part is fluid soil or sand, the construction is carried out downwards according to the depth of 0.5m section by section, firstly, hard logs (tip diameter is 3-5 cm, spacing is 10 cm) with the length of more than 1.5m are obliquely driven into the soil body part along the peripheral hole of the hole wall, then the soil body part is hollowed out, then the rock body part is chiseled out, and the soil body part is dug out, and the soil is dug out and the gaps between the hard wood piles are plugged by using clustered straw, bamboo fence or nylon woven bags during the soil digging operation, so that the soil can be filtered and blocked, and when the soil is dug to the depth of one section (about 0.5 m), if the soil (sand) is dug out from the hole bottom, the soil (sand) is blocked by using nylon woven bag sand to press the hole bottom. Binding and installing retaining wall steel bars after correcting pile holes, and pouring C30 concrete retaining walls after setting steel molds and draining accumulated water in the holes. And constructing the next section after the dado concrete is coagulated for 24 hours until the dado concrete passes through the karst cave layer.

(4) When the soil body part is in fluid soil and the slurry fluidity is very large, firstly, a nylon woven bag (permeable) is used for dry mixing 1:2, pressing cement mortar (or dry cement powder) into slurry in a cavity of a karst cave to construct a closed cofferdam, pressing the upper part of the cofferdam against the top of the karst cave, removing slurry in a pile hole after water permeates a woven bag to enable the dry cement mortar (or dry cement powder) in the bag to absorb water and condense, then setting a steel mould, pumping water accumulated in the dry hole, pouring a C30 reinforced concrete retaining wall, and constructing the next section after the retaining wall concrete condenses for 24 hours until the retaining wall passes through the karst cave layer.

2) Closed karst cave in rock layer

(1) When the filled soil body is hard clay, each section of the soil body is constructed downwards according to the working method of the hard clay layer at a depth of 1.0m until the soil body passes through the karst cave layer.

(4) When the filler in the karst cave is slurry or accumulated water with high fluidity, the slurry and accumulated water in the karst cave are discharged. If the karst cave wall rock is complete, the side depth or height of the karst cave is not large (within 1.0 m) and the pile holes are all in the karst cave, the karst cave is fully revealed, mud is washed clean, the chipped stone (grout or dry masonry) is built, the thickness of the retaining wall is reserved, and then the reinforced concrete retaining wall is constructed according to the normal state. When the side depth of the karst cave is greater than 1.0M and the height is smaller than 3.0M, the karst cave is completely disclosed, the periphery of the karst cave is cleaned, a sheet stone wall body with the thickness of 80cm is built on the outer side of the karst cave by adopting M7.5 cement mortar, the thickness of a retaining wall is reserved, and at the moment, the thickness of the retaining wall is increased by 5cm than that of the retaining wall under normal conditions, and the height of the retaining wall is 50 cm/section. When the strength of the grouted wall reaches more than 80% of the design strength, the reinforced concrete wall is constructed.

(5) When the height and the side depth of the closed karst cave are both larger than 3m, the plane trend of the karst cave is ascertained, the plane of the bridge is clearly marked, relevant image data are attached, and the construction unit organization design unit processing is submitted.

(5) Karst cave with multiple cracks

And each filling construction mode is adopted, namely, after one crack opening is blocked, the next crack hole is subjected to the construction in sequence, and particularly, the weak link of the protection wall is paid attention to.

Firstly, steel drills are used for probing the depth trend of the cracks, if necessary, wood beams are needed to be made, and cement powder is stepped on to fix karst in the cracks.

(6) Beaded karst cave

And (5) primarily determining the scale and trend of the karst cave, attaching related image data, and submitting the karst cave to construction unit organization design unit treatment.

2. Water burst

When water is gushed, water is not blocked, the water is led into the bottom by bamboo joints or water pipes, and then the water is pumped and discharged day and night by a high-lift water pump, so that the water level of the shallow pile can be reduced, and a surface is provided for pouring after hole forming.

3. Sludge

(1) When the sludge is met, the excavation height of the hole piles is reduced to 50c'm, and if the sludge amount is small, the sludge supporting wall is quickly cleaned. And filling the void behind the retaining wall with concrete caused by the mud flowing into the hole pile.

(2) The sludge is large, 1m long thread reinforcing steel bars phi 16@200 net sheets are inserted into the sludge obliquely along the pile wall, then the stratum is stabilized, and then a straw mat or a cement pocket is forced to be pressed into the sludge around along the pile wall, so that the sludge is prevented from diffusing into the pile, and the sludge in the pile is cleaned in time. And (5) continuing to excavate downwards by adopting the same method until the wall protection strength reaches the demolding strength, and entering a non-silt layer.

4. Sand meeting with flow

(1) The sand flow is not large: shortening the cyclic excavation depth, typically 0.5m or even less. The exposure time of the soil layer of the excavation layer is shortened, and the concrete retaining wall is poured in time.

(2) The sand flow amount is large: firstly, a 1m long thread reinforcing steel bar phi 16@150mm net sheet is inserted obliquely into a stable stratum (used for supporting sand filtering materials) along the pile wall, and the stable stratum and an upper reinforcing steel bar are reliably bound. Along with the increasing of depth, sand blocking filter materials such as bamboo hedges, sand bags, straws and the like are continuously added on the periphery of the reinforcing steel bars so as to prevent mud and sand outside the retaining wall from falling into the pile from the upper part, and retaining wall stirrups are continuously added and bound as soon as possible. However, the height of the pile is not too high, and is controlled within 0.5m, so that the pile has certain strength, and the pile is closed with the upper-layer retaining wall, so that peripheral sand can be effectively prevented from rushing into the pile hole. And after the excavation, the formwork is installed and concreted as soon as possible.

5. Water mill drilling process (shown in figure 4) for excavating pile foundation

(1) Application range of water mill drill construction

According to the actual situation of the site, the water mill drilling method is adopted for constructing the manual hole digging pile which is partially adjacent to the house and is not allowed to adopt blasting construction.

(2) Water mill drilling construction machine

The water mill drill mainly comprises a water mill drill, a water mill drill cylinder and a special water pump. Typically, a water mill drilling machine is provided with 3-5 water mill drilling drums, and 7 tool bits are arranged on one water mill drilling drum. The outer diameter of the water mill drilling cylinder is 16 cm, the inner diameter is 14 cm, the wall thickness is 1 cm, the height is 62 cm, and one cycle can drill 60 cm. The external diameter of the special water pump is 12 cm, and the height is 40 cm.

(4) Construction of water mill drill

The pile hole is excavated layer by layer from top to bottom.

(1) Drilling rock around: and 50-60 coring points (calculated according to the pile diameter) are arranged along the pile foundation hole wall, the coring diameter is 140mm, the coring circles are tangent to the inner wall of the locking notch, and the distance between the coring circles is 130mm. And sequentially drilling 50-60 cores on the periphery, taking out the cores with the height of about 600mm, and forming an annular free surface on the periphery of the pile core body after the outer Zhou Yanxin is taken out.

(2) Drilling intermediate rock: and drilling a core along the radius of the pile, and equally dividing the pile core rock mass into three equal parts, wherein each part accounts for 1/3 of the pile core rock mass so as to facilitate the breaking of the rock mass.

(3) Punching by an electric hand drill: the hand electric drill drills holes on the pile core rock mass, and then divides the pile rock into six equal parts.

(4) Inserting a steel wedge and striking the steel wedge to split the rock: and driving a steel wedge into a hole drilled by the radial electric hand drill along the pile foundation, hammering the steel wedge by using a large hammer to enable the rock mass to obtain a horizontal impact force, and pulling the rock along the plumb face under the action of the horizontal impact force to crack, wherein horizontal shearing and cracking can occur at the bottom. The rock mass is split in turn until the layer of pile core rock mass is fully broken.

(5) Human tooling slag and electric hoist slag: after one-time single-cycle construction, sequentially deslagging the core drilled by the water drill, deslagging from one side of the pile hole, inserting a steel wedge, and deslagging once again after the steel wedge is hit to split the rock.

(6) Because the wall of the pile foundation hole is in a zigzag shape after the water mill drills the core, rock saw teeth occupying the pile foundation space are knocked off in order to ensure that the effective pile diameter is consistent with the designed pile diameter. Marking out the center of the designed pile in the pile hole through the locking port pile protection, checking the deviation condition of the pile foundation bottom, correcting the deviation in time, marking out the drilling coring position of the next circulation periphery water mill drill, and entering the next circulation drilling pile construction.

The concrete process of slag discharging and transporting is as follows: the manual hole bottom slag loading is adopted for hole digging and slag discharging, the winch lifts the hole discharging mode to slag, the lifting speed of the winch is 0.3 m/s-0.5 m/s, the ground pushes out the open land beyond the range of the pile hole edge 3m by using the trolley, the waste soil height is not more than 1m, the hole digging waste materials are orderly and normal to be piled up and transported to a waste soil field in time, and the waste soil cannot be discarded in the red line range or outside the red line range at will.

The construction process of the steel bar engineering is as follows:

4.1 Reinforcement cage machining

1. Structure of reinforcement cage

The steel bar cage is manufactured in a sectional mode, the steel bar cage is machined in a centralized mode in a steel bar processing factory, the standard length of the steel bar cage is 9m or 12m, the number of main bar joints with the same section is not more than 50%, the joint distance is larger than 35 times of the diameter of the steel bars, adjacent joints of the main bars are staggered by 100cm and manufactured in a matched mode from top to bottom, and blanking is matched according to the actual length of the manufactured steel bar cage to ensure the total length of the steel bars. The gantry crane or the truss crane is arranged in the steel bar processing field and used for unloading raw materials, transferring finished semi-finished products and the like. In order to ensure that the reinforcement cage framework has enough rigidity, a reinforcement hoop is arranged on the inner side of the main reinforcement according to the requirements of a design drawing, so that deformation is not generated in the transportation and hanging processes.

2. Blanking and processing semi-finished products

(1) The main reinforcement of the reinforcement cage adopts a mechanical connection mode of rib stripping rolling straight thread connecting sleeve (according to the I-level joint requirement), a grinding machine is used for cutting off the threading end of the raw material of the reinforcement by about 20mm before threading the reinforcement, the incision section is ensured to be vertical to the axis of the reinforcement, and burrs cannot be left at the incision.

(2) The threading process must be operated by a professional to make the length, profile and pitch of the thread correspond to those of the sleeve and be tested to be acceptable according to the relevant regulations. The processed reinforcing steel bar wire head should be timely provided with a protective cap or screwed with a straight thread sleeve to prevent the wire teeth from being damaged. The main reinforcement wire heads of the upper section and the lower section of the reinforcement cage are matched by long and short wires, the long wires are arranged on the lower section, and the short wires are arranged on the upper section, so that the main reinforcement is convenient to connect when the sections of the reinforcement cage are hoisted.

(3) The reinforcing ring is formed by uniformly processing in a field, and the processing precision and the welding quality are strictly controlled during construction. The welding personnel can support the guard and wear the safety protection articles during construction. And (3) carefully checking the weld joint quality by technicians in construction, and using the qualified weld joint quality as a reinforcement cage for processing.

(4) The processing size and quality requirements of the spinneret are as follows:

table 1 spinneret process dimensions

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Note that: the effective thread length of the steel bar short wire head is not less than 1/2 of the length of the connecting sleeve, and the allowable error is +2P (P is the thread pitch). The effective thread length of the reinforcement bar long thread head is not smaller than the length of the connecting sleeve, and the allowable error is +2P.

TABLE 2 straight thread sleeve appearance, size and thread inspection method

TABLE 3 spinneret quality test requirements

(5) When the steel bar threads are machined, water-soluble cutting lubricating liquid is adopted; when the air temperature is lower than 0 ℃, 15-20% of sodium nitrite should be doped, and engine oil is not used as lubricating liquid or lubricating liquid is not used for threading.

(6) The appearance quality of the steel bar wire heads is checked one by one, whether teeth are full, whether teeth are broken or not and whether teeth are bald or not are checked, and the qualified wire heads are covered with protective caps for protection.

(7) The threading of the steel bars and the sleeving of one end of the threaded sleeve are completed in the back field, the steel bars with the threading at both ends are sleeved with the threaded sleeve at one end and covered with the sleeve cover, the other end of the steel bars is protected by the plastic protective sleeve, and the connection is completed in the installation field by using the pipe tongs after the steel bars are transported to the front field and installed in place.

(8) In order to ensure smooth connection of the reinforcing bars, the processed reinforcing bars are protected during transportation and hoisting, in particular to exposed threads of the reinforcing bars and internal threads of the sleeve.

(9) The straight thread die field test includes a thread die tooth test and a diameter test. The thread die tooth form inspection needs to achieve full tooth form, has no defects of broken teeth and bald teeth, is matched with the tooth form of a tooth form gauge, and ensures that the tooth surface is smooth and clean to be a qualified product. And the special caliper gauge and ring gauge for checking the diameter of the thread meet the requirement of qualified caliper gauge and ring gauge checking. And (3) randomly sampling and checking by a quality inspector through a self-checking qualified spinneret, taking 500 wire heads with the same specification as a batch, randomly performing sampling and checking for 10%, and performing re-checking.

3. Cage processing

The reinforcement cage is manufactured and formed in a centralized way by a reinforcement cage seam welder in a reinforcement factory, and is manufactured in sections. Part of the large-diameter pile reinforcement cage is formed by manually machining a jig frame.

(1) Structure of rolling welding machine for reinforcement cage

1) Dragging the guide rail; 2) A console; 3) A drag drive system; 4) A main rib material rack; 5) A steel reinforcement cage hydraulic support system; 6) A stationary rotary drive system; 7) A mobile rotary drive system; 8) A main rib fixer; 9) A main tendon duct; 10 A main rib receiving and separating system; 11 Stirrup pay-off rack; 12 A stirrup straightening mechanism; 13 Main rib feeding system.

(2) Device installation notice

1) Safety protection measures are required to be made in the whole installation process, and irrelevant personnel are strictly forbidden to lean against the near field;

2) Familiarizing with the installation step before installation, predicting potential safety hazards in the installation process, and taking measures to stop the occurrence of the potential safety hazards;

3) Preparing installation tools and equipment, and checking the connection condition of related power supplies;

4) The equipment is slowly and lightly placed in place, shake collision is forbidden, and equipment damage caused by misoperation in the installation process is prevented;

5) The leveling adjustment of the equipment is careful, and the horizontal state of the equipment can directly influence the use state and service life of the equipment;

6) The earth leakage protector and the earth wire are installed correctly, and the operation safety of the earth leakage protector and the earth wire is ensured.

(3) Working principle of reinforcement cage seam welder

The construction process of the reinforcement cage seam welder integrates main reinforcement positioning, coil straightening, stirrup winding, carbon dioxide arc welding and integral molding into a whole, and is operated in a numerical control mode. The main reinforcement of the reinforcement cage is fixed by manually penetrating through corresponding template round holes of the fixed rotary disk to corresponding holes of the movable rotary disk, the ends of the disk reinforcement (winding reinforcement) are welded on one main reinforcement first, then the winding reinforcement is wound on the main reinforcement (the movable disk is rotated and moved backwards) through rotation of the fixed rotary disk and the movable rotary disk, and welding is performed simultaneously, so that the reinforcement cage for the product is formed.

(4) The construction and production process flow of the seam welder is as shown in fig. 5:

(5) The construction steps are as follows:

1) And (3) feeding: and (3) blanking, butt welding or sleeve connecting the main ribs into the length required by the drawing in advance, and then hanging the main ribs on a main rib storage rack for later use. The main reinforcement storage rack is suitable for storing 2-27 m steel bars, is integrally formed by welding and assembling H-shaped steel, adopts a breaking structure, is separated by 2 m/m, is convenient to disassemble and transport, and can be omitted under the condition of disallowing. The coil bar is hung on a pay-off rack, and the maximum load is 2T and the height is 1.7m.

2) Penetrating and fixing

Workers shake off the main ribs and distribute the main ribs on the circumference of the distributing disc, penetrate into the guide pipes of the annular templates of the fixed disc and the movable disc, and clamp the guide pipes of the movable disc by bolts. The material distributing disc system consists of a plurality of material distributing discs, is connected with the fixed disc and can move along with synchronous rotation; the roller at the end part can reduce the rotation resistance; when the main ribs are clamped, attention is paid to the length of each dislocation to be 1m.

3) Wire threading and winding fixing of disc rib

And the disc ribs penetrate through the straightening mechanism and are welded and fixed with the main ribs in a crossing way.

4) Initial welding

And at the head of the reinforcement cage, the fixed disc and the movable disc synchronously rotate to continuously wind the disc ribs for a plurality of circles side by side, and then the disc ribs are firmly welded with the main ribs.

5) Formal welding and termination welding

Formally welding: the fixed disk and the movable disk synchronously rotate, and the movable disk simultaneously moves forward, so that the disk ribs are automatically wound on the main ribs and welded simultaneously, and a reinforcement cage product is formed.

And (5) terminating welding: at the afterbody of steel reinforcement cage, two discs continue to rotate, pause the welding, with the dish muscle around several rings side by side, then with the dish muscle end welding fixed on the main muscle, accomplish the welding.

6) Separation of reinforcement cage from rotary disk

Cutting off the winding bar, moving the moving disc forwards, and separating the reinforcement cage from the fixed disc; loosening bolts of the main rib and the movable plate template conduit; the moving disc moves forward, and the reinforcement cage is separated from the moving disc.

7) Hydraulic support for unloading cage and lowering

And a gantry crane or a manual pushing and rolling hydraulic system is adopted to push and roll the reinforcement cage down. In the whole welding process, 5 hydraulic supporting devices are required to be configured for preventing the steel reinforcement cage from being deformed due to dead weight. The hydraulic station is specially designed, adopts domestic general hydraulic elements, and is durable and has high interchangeability.

8) The moving disc is reset and ready for the next cycle

After unloading the cage, the movable tray is reset and the next cage (section) is ready to be produced. The electric control system adopts an ABB frequency converter, a PLC and a touch screen, adjusts the welding speed, randomly changes the winding distance, the winding number and the like, and is only required to be set on the touch screen without stopping the machine to adjust the machine, so that the operation is simple and easy to learn.

9) Reinforcing rib in welding

And bending the inner stirrup in advance, and after the reinforcement cage is dismounted, manually spot-welding the inner stirrup inside the reinforcement cage to play a role in reinforcing support and deformation prevention.

Spiral ribs are not arranged at the two ends of the section of each section of the reinforcement cage joint within the range of 1.5m, and binding is carried out after the on-site reinforcement cage joint is received and inspected. Finally, setting up concrete cushion blocks according to the design value of the thickness of the protective layer, adopting cake-shaped concrete cushion blocks in the engineering, wherein the strength is not lower than the strength of the designed concrete, the vertical arrangement distance of cushion blocks is 4m, 4 blocks are radially arranged at equal intervals, and the upper layer and the lower layer are arranged in a staggered manner.

And synchronously installing ultrasonic detection pipes during matching and manufacturing of the reinforcement cages. The section length of the sounding pipe is basically consistent with the section condition of the reinforcement cage. The bottom elevation of the sounding pipe is the same as the bottom elevation of the bottom joint reinforcement cage, and the top elevation is higher than the pile top by not less than 20cm. The acoustic tube joint is connected by a sleeve and is fixed by a positioning rib. When welding the sounding pipe positioning ribs, attention is paid to protecting the sounding pipe, and electric welding is prevented from penetrating through the pipe wall.

4.2.7.2 reinforcement cage storage and transportation

(1) In order to ensure that the on-site butt joint work is smoothly carried out, a main reinforcement is selected at the joint of the reinforcement cage during construction, red paint is used for marking the reinforcement bars at the two sides of the sleeve, and on-site installers enter the seat according to the red paint mark, so that the butt joint is completed. In addition, a sleeve is arranged at the end head of the main reinforcement of the top section reinforcement cage to wrap the main reinforcement, the upper end and the lower end of the sleeve are closed, and the binding force between pile head concrete and the main reinforcement is reduced, so that the pile head is broken conveniently.

(2) The identification label should be hung immediately to the steel reinforcement cage that finishes in the reinforcement yard, marks information such as pile number, festival number, the process time of steel reinforcement cage on the label, avoids makeing mistakes when depositing, transporting, brings inconvenience for the construction.

(3) The manufactured reinforcement cage is stored on a flat and dry field, 2 layers at most are stored, square timber corresponding to the equal heights of the support pads at the stiffening hoop positions is separated from the ground, so that the reinforcement cage is prevented from deforming to increase the butt joint difficulty, and meanwhile, the work of rain prevention, moisture prevention and the like is performed.

(4) When the hole digging pile is dug to the designed elevation, after checking and signing by a timely report and supervision engineer, the pile is horizontally placed and transported to the corresponding pile position by adopting a flat car, and the reinforcement cage is immediately lowered and the concrete construction is immediately carried out.

4.2.7.3 reinforcement cage installation and connection

In order to ensure that the framework is not deformed during lifting, triangular supports are welded in the reinforced framework before lifting so as to strengthen the rigidity of the framework, 2 lifting points (the positions are the top reinforcing rib positions A) are arranged at the top for vertical lifting, and 1 lifting point (the reinforcing rib positions B) is arranged at the position, 1/3 of the length of each section of the reinforcing cage from the bottom, of the reinforcing cage for turning over and lifting. And 1 phi 20 reinforcing ribs are arranged at the positions of the hanging points.

(1) When the terrain is flat, all works are ready before hoisting, and the 25t crane is commanded to be transferred to a hoisting position, a steel wire rope and a clamping ring are arranged on a steel reinforcement cage by a span worker, and a main lifting hook and an auxiliary lifting hook of the 25t automobile crane are hung.

(2) When the topography is steeper, the mode of excavation and filling is adopted, construction passageway and hoisting platform are built, the position of the platform meets the requirement that the working radius of the crane is less than or equal to 9m, the diameter of the reinforcement cage is larger, and when the length is longer, a 50t crane or other types of cranes meeting the requirement of hoisting weight are used instead, so that the hoisting safety is ensured.

(3) And after the installation condition of the steel wire rope of the crane is checked and the gravity center of the crane is stressed, the crane starts to be hung horizontally at the same time.

(4) After the steel reinforcement cage is hung to be 0.3-0.5 m away from the ground, whether the steel reinforcement cage is stable or not is checked, the rear main crane slowly lifts the hook, and the auxiliary crane is commanded to cooperate with the hook at any time according to the distance between the tail of the steel reinforcement cage and the ground.

(5) After the reinforcement cage is lifted, the main hook is lifted slowly, the auxiliary crane is matched, the distance between the reinforcement cage and the ground is kept, and finally the reinforcement cage is vertical to the ground.

(6) And (3) commanding the lifting cage of the crane to enter and position, wherein the crane rotates stably, and pulling the traction rope on the steel reinforcement cage. When the steel reinforcement cage is put down, if the condition of clamping the hole of the steel reinforcement cage is met, the steel reinforcement cage is hung down after the condition of checking the hole position, and the hole is not forced.

(7) When the steel reinforcement cage is lowered to the hanging point B, the steel wire rope and the clamping ring of the hanging point B are suspended and lowered.

(8) When the reinforcement cage continues to be inserted downwards and reaches the hanging point A, the reinforcement cage is suspended and put down, stable square timber is erected on two sides of the hole, the height consistency of the square timber is guaranteed, a 20 channel steel supporting beam is arranged on the square timber, when the rest top of the first section of reinforcement cage in the hole is about 1.5m, the supporting beam is penetrated below the uppermost layer of reinforcing ring, the reinforcement cage is slowly hooked down until the reinforcement cage completely acts on the supporting beam, at the moment, the reinforcement cage is temporarily supported on the hole, the stress condition of each place is observed, and the steel wire rope and the clamping ring of the hanging point A can be released after being stable are confirmed, so that the reinforcement cage enters the next section for installation.

(9) After the first section of reinforcement cage is lifted, the second section of reinforcement cage is lifted to the hole, and the main reinforcement is matched according to the marking.

And when the main ribs are butted, the sounding pipes in the reinforcement cage are butted, and when the main ribs are butted, the positions of the pipelines are adjusted first to ensure linearity and smoothness, and then the connection is carried out. Binding the stirrups in the connecting area after the stirrups are qualified through inspection. The stirrup joint adopts the ligature overlap joint, and overlap joint length is according to the design drawing requirement, and when the design was not stipulated, to HPB300 reinforcing bar, overlap joint length was not less than 35d, HRB400 reinforcing bar was not less than 45d. And (3) finishing the butt joint operation, lifting the reinforcement cage by a crane, removing the supporting beam, checking the condition in the hole again, and continuing to drop after no collapse and sediment are determined in the hole. In the lowering process, the hole site is aligned, the cage body is stabilized, the hook is slowly lowered, the steel reinforcement cage is prevented from colliding with the hole wall, and the pier cage and the torsion cage are strictly forbidden. And similarly, butt joint of the subsequent section reinforcement cages is carried out.

(10) Sleeve connection notice and inspection method

(1) The marked steel bars are selected as starting points, the steel bars are respectively and sequentially butted to two sides, the sleeve is immediately screwed into 3-4 screw pitches after the butt joint is finished, and gaps are likely to appear at the positions deviating from the follow-up joints due to the fact that the axes of the upper cage body and the lower cage body exist, and the steel bars can be adjusted by adopting a chain block in construction until the requirements are met.

(2) After all the steel bars are connected, 4 operators simultaneously screw the sleeve to the designed position, and all the main bars are in butt joint. The working is to ensure that the lengths of screw-in two ends of the sleeve are equal, the ends of the connected reinforcing steel bars are mutually propped up at the center of the sleeve, the axes of the two reinforcing steel bars at the joint are on the same line, the deviation is smaller than 0.1d, the exposed threads on one side of the joint are not more than 2p (p is the pitch of the threads) after the joint is installed, and other straight threaded joints which cannot be propped up are fastened by means of adding locking nuts, propping up bosses and the like.

(3) After the installation is completed, the torque wrench is adopted to check the tightening torque, and the minimum tightening torque value is as follows:

table 4 minimum tightening torque values for connection installation of straight threaded joints

Diameter of steel bar (mm)	22～25	28～32
			Tightening torque (N.m)	260	320

(11) Steel reinforcement cage location

(1) Elevation control

The length of the positioning rib is calculated by the measured elevation of the orifice measured by the level gauge, and the welding and positioning are performed after repeated checking.

(2) Plane position control

And (3) pulling a cross wire on the top opening of the reinforcement cage, finding out the center of the reinforcement cage, and finding out the pile position center according to the pile protection, wherein the center of the reinforcement cage coincides with the pile position center when the reinforcement cage is positioned.

After accurate positioning, the hanging ribs are welded on the main ribs of the reinforcement cage, and the hanging ribs are welded with the locking port supporting beam or the embedded part, so that the floating cage phenomenon is avoided in the process of pouring concrete.

And after the whole reinforcement cage is in place, reporting and supervising engineers detect the perpendicularity of the reinforcement cage and the thickness of the protective layer, and entering the next working procedure after the detection is qualified.

Acoustic pipe installation

And hot-rolled seamless steel pipes are arranged in each pile foundation at equal intervals according to the design requirement and used for detecting the integrity of the pile body by ultrasonic waves, and the bottoms of the steel pipes are sealed so as to prevent concrete from leaking in. Before the acoustic pipes are installed, whether each acoustic pipe is unobstructed or not needs to be checked, and iron wires are bent into an 8 shape to be bound on each reinforcing stirrup. In principle, a section of acoustic tube is installed and is filled with a section of clean water, and a certain time is waited for to check whether the water surface in the tube is lowered. The next section of reinforcement cage can be installed and connected with the detection pipe after the sound detection pipe is filled with water until the top is finally filled with clear water, the sound detection pipe is sealed by a wood plug or a rubber sleeve and is tightly tied by iron wires, the detection pipe is ensured to be sealed, and mud and mortar are prevented from entering. The sounding pipe is straight and has a curvature of not more than 5mm/m; the sections of the two ends of the sounding pipe are vertical to the axes of the sounding pipe; the cross section and the edge of the incision of the sounding pipe must be polished smoothly without burrs so as not to hurt the sealing ring when the cannula is installed.

The specific process of the final hole detection is as follows:

The concrete process of the steel bar engineering construction is as follows:

The concrete process of pile foundation concrete pouring is as follows:

5.1, arranging a blanking hopper, a stringing barrel or a guide pipe:

5.2, pouring pile body concrete, wherein the concrete process is as follows:

v-quantity required for pouring first concrete (m ³ )；

D-pile hole diameter (m);

H ₂ -primary depth of embedding (m) of the catheter;

d-inner diameter of the catheter (m);

h ₁ ＝H _W ·γ _W /γ _c 。

wherein:

H _w -height of free surface of slurry to top surface of concrete (m)

γ _w -mud weight (g/cm 3);

γ _c -concrete weight (g/cm 3);

D＝1.5m：V＝2.8m ³ ；

D＝1.6m：V＝3.2m ³ ；

D＝1.8m：V＝3.9m ³ ；

D＝2.0m：V＝4.7m ³ ；

D＝2.2m：V＝5.7m ³ ；

D＝2.5m：V＝7.2m ³ 。

(4) And the pile body concrete is cast and formed at one time.

The concrete process of pile head breaking is as follows:

The concrete process of pile foundation detection is as follows:

The foregoing is merely a preferred embodiment of the present invention and it should be noted that modifications and adaptations to those skilled in the art may be made without departing from the principles of the present invention, which are intended to be comprehended within the scope of the present invention.

Claims

1. The manual hole digging pile construction method is characterized in that: pile position positioning measurement, locking construction, orifice arrangement, pile hole excavation, slag discharge transportation, final hole detection, steel bar engineering construction, pile foundation concrete pouring, pile head breaking and pile foundation detection to finish construction.

2. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of pile position positioning measurement and locking construction is as follows:

3. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of slag discharging and transporting is as follows: the manual hole bottom slag loading is adopted for hole digging and slag discharging, the winch lifts the hole discharging mode to slag, the lifting speed of the winch is 0.3 m/s-0.5 m/s, the ground pushes out the open land beyond the range of the pile hole edge 3m by using the trolley, the waste soil height is not more than 1m, the hole digging waste materials are orderly and normal to be piled up and transported to a waste soil field in time, and the waste soil cannot be discarded in the red line range or outside the red line range at will.

4. The method for constructing the manual hole digging pile according to claim 1, wherein: the specific process of the final hole detection is as follows:

5. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of the steel bar engineering construction is as follows:

6. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of pile foundation concrete pouring is as follows:

5.1, arranging a blanking hopper, a stringing barrel or a guide pipe:

5.2, pouring pile body concrete, wherein the concrete process is as follows:

2. The concrete is mixed intensively, automatically metered, transported in a tank truck, and poured into the mold at a temperature not lower than +5 ℃ and not higher than +30 ℃, otherwise, corresponding measures approved by a supervision engineer are adopted, when the concrete is poured by adopting a tube-stringing method, two vibrating workers in each hole adopt 50-type inserted vibrating bars for vibrating operation; when pouring is performed by adopting a conduit method, the slump test is carried out on the concrete on the construction site according to the requirement of pouring underwater concrete, and the slump is controlled between 16 cm and 22 cm;

v-quantity required for pouring first concrete (m ³ )；

D-pile hole diameter (m);

H ₁ the distance from the bottom of the pile hole to the bottom end of the guide pipe is 0.3-0.4 m;

H ₂ -primary depth of embedding (m) of the catheter;

d-inner diameter of the catheter (m);

h ₁ ＝H _W ·γ _W /γ _c ；

wherein:

H _w -height of free surface of slurry to top surface of concrete (m)

γ _w -mud weight (g/cm 3);

γ _c -concrete weight (g/cm 3);

D＝1.5m：V＝2.8m ³ ；

D＝1.6m：V＝3.2m ³ ；

D＝1.8m：V＝3.9m ³ ；

D＝2.0m：V＝4.7m ³ ；

D＝2.2m：V＝5.7m ³ ；

D＝2.5m：V＝7.2m ³ ；

(4) And the pile body concrete is cast and formed at one time.

7. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of pile head breaking is as follows:

and a second step of: the steel bar is cut in a circular way by adopting a cutting machine, so that the steel bar is deeply formed, the subsequent air pick operation is convenient, and the steel bar protection layer is not damaged;

sixth step: the pile head concrete breaking whole is lifted out by a crane, the pile head and the pile body are completely separated before lifting, then lifting is carried out, the pile head concrete breaking whole is lifted as slowly as possible to avoid damaging steel bars, and in the lifting process, personnel are away from an operation range so as to prevent accidents caused by falling of the pile head, and the pile head is placed in a place away from a foundation pit after being lifted out;

8. The method for constructing the manual hole digging pile according to claim 1, wherein: the concrete process of pile foundation detection is as follows: