CN117026971A

CN117026971A - Construction method of anti-deviation pile under thermoplastic sludge geological condition

Info

Publication number: CN117026971A
Application number: CN202310949325.3A
Authority: CN
Inventors: 贝宝荣; 凌雅纯
Original assignee: Shanghai Baoye Group Corp Ltd
Current assignee: Shanghai Baoye Group Corp Ltd
Priority date: 2023-07-31
Filing date: 2023-07-31
Publication date: 2023-11-10

Abstract

The application relates to a construction method of an anti-deviation pile under a thermoplastic silt geological condition, which comprises the following steps: carrying out improvement treatment on soft soil of silt geology before tubular pile construction; step two: before the pipe pile is implemented, the construction of the anti-extrusion ditch and the stress release hole is carried out; step three: quality monitoring is carried out in the pipe pile construction process; step four: quality monitoring is carried out in the earthwork excavation engineering; step five: and (5) carrying out displacement monitoring in the pipe pile construction process. The application provides a construction method for effectively preventing offset piles and broken piles in the PHC pipe pile construction process under a deep and plastic silt geological state.

Description

Construction method of anti-deviation pile under thermoplastic sludge geological condition

Technical Field

The application relates to civil engineering, in particular to a construction method of an anti-deviation pile under a thermoplastic sludge geological condition.

Background

1. The silt type soft soil layer has high compressibility, thixotropy and rheological property, the site surface soil is poor in site endurance, the pile machine is in the moving process, the landing leg direct connection station of the pile machine walking part is pressed on the pile top or the pile top soft soil layer to form a strong extrusion effect on the surface soil layer, and when the upper part of the foundation soil is provided with a thicker soft soil layer or the lower part of a thinner hard soil layer on the surface of the ground is provided with a thicker soft soil layer, the pipe pile can be pushed and inclined, and even broken. Meanwhile, the impact of the excavating machinery, the rolling of heavy vehicles or construction machinery can cause damage and deviation of the pipe pile.

2. The prestressed concrete pipe pile belongs to a soil-squeezing pile, when a large-area dense pile group is applied, the soil squeezing of the pile which is driven first is often inclined, and when the pipe pile is constructed at too high speed, the soil squeezing effect is aggravated, so that the pile is deviated and broken.

3. Under the condition that the bearing stratum level difference of engineering geology is too large and has obvious abrupt slope, the actual single pile load is uneven or slides at the abrupt slope, and the serious person is inclined and broken. Especially pile under the geological condition of 'soft upper part and hard lower part, soft and hard abrupt change', pipe pile quickly penetrates through soft soil covering layer to encounter hard soil layer, penetration degree suddenly becomes small, pile body rebound is severe, and pile body is easy to break.

4. In the process of digging, as the mobility of the mucky soil is high, piling extrusion force accumulated in the soil body and water in gaps in the soil layer are pressed to be released for digging, so that the flowing of the mucky soil to the digging direction is further enhanced; and because the prestressed pipe pile is long and has small resistance to the horizontal, the prestressed pipe pile is inclined towards the excavation direction along with the displacement of the soil body, and a large amount of displacement of the pile top can be caused.

Under the geological conditions, the PHC pipe pile construction is carried out by adopting the traditional construction scheme, so that the pile deflection and pile breakage are very easy to occur.

Disclosure of Invention

The application aims to overcome the defects of the prior art, provides an anti-deflection pile construction method under the geological condition of plastic silt, and solves the problems that deflection piles and broken piles are easy to occur when a silt soft soil layer is used for pile construction.

In order to solve the technical problems, the application is realized as follows:

a construction method of an anti-deviation pile under a geological condition of a thermoplastic sludge is characterized by comprising the following steps:

step one: carrying out improvement treatment on soft soil of silt geology before tubular pile construction;

step two: before the pipe pile is implemented, the construction of the anti-extrusion ditch and the stress release hole is carried out;

step three: quality monitoring is carried out in the pipe pile construction process;

step four: quality monitoring is carried out in the earthwork excavation engineering;

step five: and (5) carrying out displacement monitoring in the pipe pile construction process.

The construction method of the anti-deviation pile under the geological condition of the thermoplastic sludge is characterized by comprising the following steps of: the soft soil improvement treatment method for the silt geology comprises the following steps: carrying out drainage treatment by adopting a regenerated plastic drainage plate, and carrying out drainage plate construction in the pipe pile construction and foundation pit excavation range by adopting a soft foundation treatment mode of a consolidation method; adopting a recycled plastic drainage plate, wherein the section size of the drainage plate material is 4mm multiplied by 100mm, the construction is 1000mm, and the construction depth is 6 meters beyond the excavation depth; the crawler type plate inserting machine is adopted for manual auxiliary positioning during construction, the running direction of the crawler wheels is required to be consistent with the row direction of the drainage plates, and drainage ditches with the distance of less than 50m are excavated in the field after the construction of the drainage plates is completed;

the passive area and the pit in the pit are reinforced by adopting a single-shaft cement stirring pile, the single-shaft stirring pile adopts a two-stirring two-spraying pile forming process, the cement soil stirring pile adopts 42.5 ordinary Portland cement, the cement doping amount is 15-18%, the water cement ratio of cement paste is 0.5, the treatment depth is not less than 9m when entering the bottom of the foundation pit, the treatment range is the periphery of the foundation pit and pit positions in the pits such as an elevator shaft, a water collecting well and the like, the reinforcing width of each side is not less than 3 rows of stirring piles, and earth excavation can be carried out in the age of more than 28 days.

The construction method of the anti-deviation pile under the geological condition of the thermoplastic sludge is characterized by comprising the following steps of: the construction method for preventing the ditch from being squeezed comprises the following steps: before the tubular pile is constructed, partitioning a large field, wherein each area is not more than 3000 square meters, and digging anti-extrusion grooves with the width of 1m and the depth of 1.5m around the field and between the areas;

the construction method of the stress release hole comprises the following steps: releasing pre-drilling stress in the field, wherein the aperture is 1m, the distance is 15m, the depth of the holes is 18m, and the holes are arranged in a quincuncial shape in the field; in order to prevent pile holes from collapsing before static pressure pile construction, mao Zhulong with the through length phi 900 is placed in the holes, the phyllostachys pubescens cage is formed by bundling 8 phyllostachys pubescens slices with the width of 3cm, reinforcing steel bars with the diameter of 12mm and the distance of 1.0m are required to be used as circular hoops in the phyllostachys pubescens cage, plastic woven bags are wrapped outside the phyllostachys pubescens cage, and stones are placed at the bottom in the placing process to prevent the phyllostachys pubescens cage from floating upwards.

The construction method of the anti-deviation pile under the geological condition of the thermoplastic sludge is characterized by comprising the following steps of: the quality monitoring method in the pipe pile construction process comprises the following steps:

1) The pile testing work is needed before the large-area pile is pressed, the length of the pipe pile is determined according to the pile testing condition, and meanwhile, the pile conveying length reaches the designed pile top elevation position as much as possible, so that the problem that the pile is over high in design elevation above the pile top after the pile is pressed to meet the requirement, the soil is inconvenient to excavate, and the lateral pressure of silt soil to the pile is increased is avoided;

2) Pre-drilling a stress release hole and preventing a ditch from being squeezed before piling, releasing stress caused by piling, and preventing the engineering pile from tilting;

3) Building rubbish must be paved and rolled on the ground surface, so that the ground endurance of the ground surface meeting the design requirement is ensured, the pile sinking sequence is correctly selected, and the principle of 'deep before shallow, dense before sparse' is followed;

4) Before pile sinking, checking pile components, checking whether the top surface of the pile is concave-convex, whether the plane of the pile top is vertical to the axis of the pile, and whether the pile tip is inclined, wherein the pile which does not meet the standard requirements cannot be used or can be used after being repaired;

5) In the pile stabilizing process, if the pile is found to be not vertical and should be corrected in time, when the pile is driven to a certain depth and then is inclined seriously, the pile is not corrected by adopting a frame moving method, the pile is pulled out, and the pile hole is backfilled and then is constructed again; when pile extension is carried out, the upper section of pile and the lower section of pile are ensured to be on the same axis, and the joint part is strictly executed according to the operation requirement;

6) For pile body floating, displacement and ground uplift caused by soil squeezing effect, the pile body floating adopts a redrying construction process, soil or water in a tube core is removed before redrying, the removing depth is not less than 50cm, the clearance between a pile cap and the periphery of a pile is controlled to be 5-10 meshes during redrying, a buffer pad is placed between a hammer and the pile cap, and between the pile cap and the pile, and the thickness of the buffer pad after compaction is not less than 120 mm; the hammer, the pile cap and the pile body are on the same central line; when the re-driving is started, the low gear re-driving is used for l to 3 times so as to adjust the straightness and activate the pile body; marking scales on a pile driver, tracking and observing the sinking amount by using a level gauge, and selecting an operator with abundant experience to operate; meanwhile, the throttle is controlled timely, the hammering height is controlled to be 400-600 mm finally, and the hammer can be stopped by hammering 10 beats after the pile is not sunk on the premise of meeting the hammering energy; and (5) observing the reset condition in time, and providing a guiding suggestion, and stopping the hammer in time after resetting.

The construction method of the anti-deviation pile under the geological condition of the thermoplastic sludge is characterized by comprising the following steps of: the quality monitoring method in the earthwork excavation project comprises the following steps:

1) Flexible partition construction is carried out according to the engineering volume and construction stage, the excavation is preferably carried out uniformly layer by layer, the excavation sequence strictly follows the principles of layered excavation, support and then excavation, and large foundation pit and small excavation, and the partition excavation is carried out; the thickness of each layer of soil of the silt should not exceed 1m, the first digging block and the later digging block are used for slope releasing, and the gradient is not more than 40 degrees; after the pit bottom elevation is dug, the artificial soil repairing is changed into 300mm above the designed elevation, a piece of cushion layer of the soil is repaired, and a piece of cushion layer of the soil is constructed in time, meanwhile, the elevation is also needed to be noted, and the over-digging is prevented, so that the adverse phenomena of soil gushing and the like caused by pressure difference generated after the soil is unloaded are avoided;

2) Tightly forbidden to excavate while pressing piles, and excavating the piles completely at least 15d apart to facilitate elimination of cohesive stress of soil formed in the pressed piles; the excavator and the earth-moving machine walk on the roadbed plane, command is set, the machine is strictly forbidden to collide with engineering piles in the process of excavating earth, and overload is strictly forbidden;

3) In the process of digging, the engineering piles higher than the designed elevation are subjected to pile cutting in sections according to the higher data in the process of digging; cutting off pile heads when the pile is excavated 50-100 mm higher so as to prevent the engineering pile from tilting due to unbalanced soil pressure at two sides of the pile;

4) Monitoring foundation pit, horizontal displacement and settlement according to the scheme, wherein the horizontal displacement rate is not more than 1 cm/d, and the total displacement amount of continuous 3 d is less than 2cm; in the foundation pit excavation process, a person is regularly scheduled to observe, if abnormal conditions exist, continuous observation is carried out, and each relevant unit is timely notified to be convenient to process in time; and meanwhile, emergency precautions are taken to prevent emergency.

The construction method of the anti-deviation pile under the geological condition of the thermoplastic sludge is characterized by comprising the following steps of: the displacement monitoring method in the tubular pile construction process comprises the following steps: after the construction of each pile is completed, a monitoring point position is set at the top of the pipe pile in time, the constructed supporting pile, the constructed upright pile and the pipe pile are monitored by marking with red paint at least once a day until the earth excavation is completed, monitoring data are recorded, and compared with early monitoring data, if problems are reported in time, emergency measures are taken.

The beneficial effects of the application are as follows: according to the technical scheme, the application provides the anti-deviation pile construction method under the geological condition of the hydraulic silt, and the method comprises the steps of firstly, improving soft soil of the silt geology before the construction of the pipe pile; the construction of the anti-extrusion ditch and the stress release hole is carried out before the pipe pile is implemented; quality monitoring is carried out in the pipe pile construction and earth excavation processes; finally, monitoring displacement in the pipe pile construction process; under the soft foundation condition of a deep silt layer, the application has the advantages that the inclination, the deviation and the pile breakage conditions generally reach about 10% under the construction process of using the traditional direct pile sinking, and under the control of the construction method and the steps, the occurrence of the deviation pile and the pile breakage is greatly reduced, the deviation pile and the pile breakage rate can be effectively controlled within 3% through practice, and the application has important engineering significance for shortening the construction period and saving the construction cost.

Drawings

The application is described in further detail below with reference to the attached drawings and embodiments:

FIG. 1 is a drainage plate arrangement;

fig. 2 is a plan view of a stress relief hole.

Detailed Description

The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are some, but not all embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the application, are intended to be within the scope of the claimed application based on embodiments of the present application.

A construction method of an anti-deviation pile under a geological condition of a thermoplastic sludge comprises the following steps:

Specifically, the soft soil improvement treatment method for silt geology comprises the following steps: and adopting an SPB-B type regenerated plastic drainage plate to carry out hydrophobic treatment. According to the site conditions, in order to effectively improve the property of the site soft soil, a consolidation method is adopted as an effective soft foundation treatment mode, and drainage plate construction is carried out in the tubular pile construction and foundation pit excavation range. The SPB-B type regenerated plastic drain board is adopted, the section size of the drain board material is 4mm multiplied by 100mm, the construction is 1000mm (the arrangement is shown in figure 1), and the construction depth is 6 meters beyond the excavation depth. During construction, the crawler-type board inserting machine is adopted for manual auxiliary positioning, the running direction of the crawler wheels is consistent with the row direction of the drainage board (the direction of the transverse road base), the sand cushion layer is damaged by tight turning, turning around and the like, and after the construction of the drainage board is completed, drainage ditches with the distance of less than 50m are excavated in the field, so that drainage is facilitated.

In the foundation pit supporting design, a passive area and a pit in the pit are reinforced by adopting 800@700 single-shaft cement stirring piles, the single-shaft cement stirring piles adopt a two-stirring two-spraying pile forming process, the cement soil stirring piles adopt 42.5 ordinary silicate cement, the cement doping amount is 15-18%, the cement ratio is 0.5, the treatment depth is not less than 9m when entering the foundation pit bottom, the treatment range is around the foundation pit and pit positions in the pits such as an elevator shaft, a water collecting well and the like, each side is reinforced by not less than 3 rows of stirring piles, and earth excavation can be carried out in an age of more than 28 days.

The water content of the silt layer can be effectively reduced after the soft foundation treatment, the bearing capacity of foundation soil is improved, and the requirement of pile foundation construction is basically met. In the process of excavation of the foundation pit, the engineering pile can be effectively protected.

Specifically, the construction method for preventing the ditch from being squeezed comprises the following steps: before the tubular pile is constructed, partitioning a large field, wherein each area is not more than 3000 square meters, and digging anti-extrusion grooves with the width of 1m and the depth of 1.5m around the field and between the areas;

the construction method of the stress release hole comprises the following steps: the pre-drilling stress in the field is released, the aperture is 1m, the distance is 15m, the depth of the hole is 18m, and the pre-drilling stress is arranged in a quincuncial shape in the field (the layout view is shown in figure 2). In order to prevent pile holes from collapsing before static pressure pile construction, mao Zhulong with the through length phi 900 is placed in the holes, the phyllostachys pubescens cage is formed by bundling 8 phyllostachys pubescens slices with the width of 3cm, reinforcing steel bars with the diameter of 12mm and the distance of 1.0m are required to be used as circular hoops in the phyllostachys pubescens cage, plastic woven bags are wrapped outside the phyllostachys pubescens cage, and stones are placed at the bottom in the placing process to prevent the phyllostachys pubescens cage from floating upwards.

Specifically, the quality monitoring method in the tubular pile construction process comprises the following steps:

Specifically, the quality monitoring method in the earthwork excavation project comprises the following steps:

Specifically, the displacement monitoring method in the tubular pile construction process comprises the following steps: after the construction of each pile is completed, a monitoring point position is set at the top of the pipe pile in time, the constructed supporting pile, the constructed upright pile and the pipe pile are monitored by marking with red paint at least once a day until the earth excavation is completed, monitoring data are recorded, and compared with early monitoring data, if problems are reported in time, emergency measures are taken.

While the present application has been described in detail with reference to the embodiments, it will be apparent to those skilled in the art that the foregoing embodiments may be modified or equivalents may be substituted for some of the features thereof, and any modification, equivalent substitution, improvement, etc. within the spirit and principles of the present application should be included in the scope of the present application.

Claims

1. A construction method of an anti-deviation pile under a geological condition of a thermoplastic sludge is characterized by comprising the following steps:

2. The method for constructing the anti-deviation pile under the geological condition of the hydraulic sludge according to claim 1, which is characterized in that: the soft soil improvement treatment method for the silt geology comprises the following steps: carrying out drainage treatment by adopting a regenerated plastic drainage plate, and carrying out drainage plate construction in the pipe pile construction and foundation pit excavation range by adopting a soft foundation treatment mode of a consolidation method; adopting a recycled plastic drainage plate, wherein the section size of the drainage plate material is 4mm multiplied by 100mm, the construction is 1000mm, and the construction depth is 6 meters beyond the excavation depth; the crawler type plate inserting machine is adopted for manual auxiliary positioning during construction, the running direction of the crawler wheels is required to be consistent with the row direction of the drainage plates, and drainage ditches with the distance of less than 50m are excavated in the field after the construction of the drainage plates is completed;

3. The method for constructing the anti-deviation pile under the geological condition of the hydraulic sludge according to claim 1, which is characterized in that: the construction method for preventing the ditch from being squeezed comprises the following steps: before the tubular pile is constructed, partitioning a large field, wherein each area is not more than 3000 square meters, and digging anti-extrusion grooves with the width of 1m and the depth of 1.5m around the field and between the areas;

4. The method for constructing the anti-deviation pile under the geological condition of the hydraulic sludge according to claim 1, which is characterized in that: the quality monitoring method in the pipe pile construction process comprises the following steps:

5. The method for constructing the anti-deviation pile under the geological condition of the hydraulic sludge according to claim 1, which is characterized in that: the quality monitoring method in the earthwork excavation project comprises the following steps:

6. The method for constructing the anti-deviation pile under the geological condition of the hydraulic sludge according to claim 1, which is characterized in that: the displacement monitoring method in the tubular pile construction process comprises the following steps: after the construction of each pile is completed, a monitoring point position is set at the top of the pipe pile in time, the constructed supporting pile, the constructed upright pile and the pipe pile are monitored by marking with red paint at least once a day until the earth excavation is completed, monitoring data are recorded, and compared with early monitoring data, if problems are reported in time, emergency measures are taken.