CN114319372B - Construction method of anchorage supporting structure - Google Patents

Abstract

The application provides a construction method of an anchorage supporting structure, which comprises the following steps: (1) Constructing a pile foundation and presetting guide grooves on two sides of the pile foundation along the circumferential direction of the foundation pit according to the construction position of a preset boundary pile foundation of the foundation pit to be constructed; (2) Determining the position of a second-stage groove between two adjacent pile foundations and excavating; (3) Constructing an underground wall at the secondary slot to connect adjacent pile foundations to form a whole; (4) Repeating the steps until the construction of all pile foundations, the secondary trough and the underground wall is completed; (5) And constructing the top beam on the top of the constructed pile foundation and the underground wall at the second-stage groove. The application has the advantages that lining and support do not need to be additionally applied in the construction process, the construction period is shortened to a great extent, and the construction cost is reduced.

Description

Construction method of anchorage supporting structure

Technical Field

The application relates to the field of foundation pit supporting, in particular to a construction method of an anchorage supporting structure.

Background

At present, with the development of society, urban land resources are more and more scarce, and when buildings above the ground cannot meet the requirements of people, more and more underground space use requirements can be caused.

At present, in the process of constructing an underground space, particularly when a deep foundation pit retaining wall is constructed, although some retaining walls adopt an occlusive pile design to simultaneously achieve the purposes of retaining soil and water stopping, in order to ensure that the retaining soil of a deep foundation pit can be achieved, anchor rods are often adopted to enhance the pressure resistance of the retaining soil of a pile body, the pressure of the soil body of the deeper foundation pit is higher, the number of the anchor rods which need to be adopted is increased, or the pile body for manufacturing the retaining wall can be completely replaced by a concrete pile body to improve the folding resistance, however, the two methods can lead to higher cost, moreover, the compactness of occlusion of the occlusive pile retaining wall in the design is already determined when the pile body is poured, and the compactness is difficult to change in the later period once the problem occurs, so that the water stopping effect is poor.

Disclosure of Invention

The application aims to provide the construction method of the anchorage supporting structure, which is convenient to construct, high in construction efficiency and capable of shortening the construction period.

In order to achieve the above object, the present application provides the following technical solutions:

a construction method of an anchor supporting structure comprises a pile foundation and a second-stage groove section wall, wherein the pile foundation and the second-stage groove section wall are arranged along the periphery of a foundation pit at intervals, and all the pile foundations are connected into a whole through the second-stage groove section wall, and the construction method comprises the following steps:

(1) Constructing a pile foundation and presetting guide grooves on two sides of the pile foundation along the circumferential direction of the foundation pit according to the construction position of a preset boundary pile foundation of the foundation pit to be constructed;

(2) Determining the position of a second-stage groove between two adjacent pile foundations and excavating;

(3) Constructing an underground wall at the second-stage groove to connect adjacent pile foundations into a whole;

(4) Repeating the steps until the construction of all pile foundations, the secondary trough and the underground wall is completed;

(5) And constructing the crown beam on the top of the constructed pile foundation and the underground wall at the second-stage groove.

Further setting: still include before the construction pile foundation, along the step of pile foundation circumference construction cement mixing stake, it is adjacent each other interlock between the cement mixing stake.

Further setting: the construction pile foundation in the step (2) comprises the following steps:

inserting and driving a steel pile casing on the inner side of the cement mixing pile, and excavating and forming holes by using a drilling machine;

putting down the prefabricated pile foundation reinforcement cage and the concrete pouring guide pipe;

and (5) utilizing the concrete pouring guide pipe to pour the pile foundation concrete, and finishing the construction of the pile foundation.

Further setting: after the drilling machine excavates and forms a hole, detecting the top elevation of the steel casing, the depth of a pile foundation hole, the thickness of sediment at the bottom of the hole, the hole diameter of the pile foundation hole and the verticality of the pile foundation;

and cleaning the pile foundation hole after the detection is finished so as to remove drilling slag and a sediment layer in the pile foundation hole.

Further setting: before the pile foundation reinforcement cage is put down, limiting steel boxes are correspondingly inserted into two sides of the steel casing so as to reserve a position of a guide groove on the pile foundation;

and after the concrete of the pile foundation is initially set, removing the limiting steel box.

Further setting: before the pile foundation reinforcement cage is placed downwards, lofting is carried out according to the reinforcement cage angular points and positioning pile protectors are made;

when the pile foundation steel reinforcement cage is transferred, the verticality of the transfer of the pile foundation steel reinforcement cage is ensured by utilizing the positioning pile protection and the limiting steel box.

Further setting: and (4) before the step (3) is constructed, pre-arranging guide walls at the construction positions of the second-stage grooves, wherein the guide walls at the positions of the second-stage grooves comprise two L-shaped reinforced concrete walls which are respectively arranged at two sides of the second-stage grooves along the preset boundary of the foundation pit, and excavating the second-stage grooves when the concrete strength of the guide walls reaches more than 70% of the design strength.

Further setting: in the step (3), excavating the second-stage groove by adopting a pure milling method and/or a chiseling and milling method;

the pure milling method adopts grab milling to form a groove, when an upper sludge stratum is constructed, a rope grab bucket is adopted to open a hole, and when strong-medium weathered rock is constructed at the lower part, the groove is milled by using a groove milling machine;

the drilling and milling method is used for replacing a standard wheel of a slot milling machine with a cone pulley under the condition of high rock strength, and adopts a steel wire rope crane heavy chisel to match with the slot milling machine for excavation.

Further setting: after the second-stage groove is milled, the hole cleaning and slurry changing are carried out on the second-stage groove by using a suction pump method through a groove milling machine and a slurry separation system of the groove milling machine, a milling head of the groove milling machine is placed at the bottom of the second-stage groove, a milling wheel is kept to rotate, slurry pumps in the milling head convey slurry at the bottom of the groove to a slurry separator on the ground, large-particle drilling slag is removed through a vibrating screen of the slurry separator, then the slurry enters a cyclone to separate fine powder and sand in the slurry, the purified slurry flows back into the second-stage groove, and the process is repeated in a circulating mode so as to complete the replacement of the slurry in the second-stage groove.

Further setting: the construction of the second-stage groove section wall in the step (4) comprises the following steps:

hoisting a prefabricated second-stage groove reinforcement cage, and ensuring the downward verticality of the second-stage groove reinforcement cage;

placing a second-stage groove pouring guide pipe, wherein the placing center of the second-stage groove pouring guide pipe and the center of the pile foundation are positioned on the same line, and cleaning the second-stage groove by using the second-stage groove pouring guide pipe before pouring concrete;

the concrete is poured to form the underground wall to connect the adjacent pile foundations into a whole.

Further setting: the method for forming the underground wall at the secondary trough by pouring concrete comprises the following steps:

the large hopper is utilized for primary concrete pouring, the large hopper is filled with concrete, then a valve switch of the large hopper is opened, the concrete is poured into the hole bottom along a second-stage groove pouring guide pipe, and the concrete tank truck continuously replenishes the concrete into the large hopper at the same time until the first batch of concrete is poured;

and replacing the large hopper with a small hopper, arranging a pouring frame, pouring concrete through the small hopper and the second-stage groove pouring guide pipe, and lifting and removing the second-stage groove pouring guide pipe through the pouring frame when the embedding depth of the second-stage groove pouring guide pipe exceeds 6m until the pouring of all the concrete is completed.

Further setting: after the construction of the pile foundation and the underground wall at the second-stage groove is finished, the outer side of the joint of the pile foundation and the underground wall at the second-stage groove is subjected to high-pressure rotary pile spraying to seal water.

Further setting: the crown beam is divided into four length units for construction, a post-pouring section is arranged between every two adjacent units, and the construction of the crown beam comprises the following steps:

excavating a top beam foundation pit at the top of the pile foundation and the underground wall at the second-stage groove, wherein the top beam foundation pit is excavated by slope excavation;

chiseling the super-poured concrete of the pile foundation and the underground wall at the secondary trough to expose a fresh concrete surface;

installing a crown beam template and an embedded part, wherein the crown beam template comprises a side mold and an end mold, and the embedded part comprises a connecting rib of a cable saddle foundation and an anchor block, a ladder stand installation embedded part, an anti-segregation guide pipe bracket, an operation platform embedded part, a foundation pit construction water supply pipe embedded part and a foundation pit safety protection railing embedded part;

and symmetrically pouring the length units of the crown beam along the circular arc, and finally pouring a post-pouring section to connect the four length units to form the integral crown beam.

Compared with the prior art, the scheme of the application has the following advantages:

according to the construction method of the anchorage supporting structure, the steps are simple, lining and supporting do not need to be additionally applied in the construction process, the construction period is shortened to a great extent, and the construction cost is reduced; the construction of the access road is carried out before the construction, the construction of workers and the storage of materials are facilitated, and the construction efficiency is greatly improved.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

Fig. 1 is a schematic plan view of an anchor support structure of the present application;

fig. 2 is a schematic structural view of an anchor supporting structure of the present application;

fig. 3 is a schematic structural diagram of a pile foundation and a second-stage groove in the anchor supporting structure of the present application;

fig. 4 is a schematic elevation structure view of a pile foundation, a secondary trough and a cement mixing pile in the anchor supporting structure of the present application;

fig. 5 is a schematic view of a vertical structure of an annular access passage in the tie back support structure of the present application;

fig. 6 is a schematic flow diagram of a construction method of the anchor support structure according to the present application.

In the figure, 1, pile foundation; 11. a steel casing; 2. a second-stage groove; 3. stirring the piles with cement; 4. an annular access way; 41. supporting the mixing pile; 42. a drainage ditch; 43. a sedimentation tank; 44. a anchorage material storage site; 5. a crown beam.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present application and are not to be construed as limiting the present application.

Referring to fig. 1 to 6, aiming at the problem of poor water stopping performance of the existing foundation pit cofferdam, the application provides an anchorage supporting structure and a construction method thereof, a supporting scheme combining row piles and milling joints is adopted, the water stopping performance of the anchorage supporting structure is greatly improved, no lining or support is needed in the construction process, the construction period can be shortened, and the construction cost is reduced.

Please refer to fig. 1, fig. 2 and fig. 3, the anchor supporting structure includes a plurality of pile foundations 1 annularly arranged along the periphery of the preset boundary of the foundation pit, two adjacent pile foundations 1 are connected to form a whole by excavating a second-stage groove 2 and setting an underground wall, and guide grooves for guiding the excavation of the second-stage groove 2 are reserved on both sides of the circumference of the preset boundary of the foundation pit of each pile foundation 1, and the guide grooves are communicated with the second-stage groove 2, so that the underground wall subsequently constructed in the second-stage groove 2 is embedded with the pile foundations 1 connected therewith. The gomphosis sets up the joint strength that can strengthen underground wall and pile foundation between the underground wall of second phase groove department and the pile foundation for the pile foundation forms the continuous soil retaining supporting structure who has good prevention of seepage, cut-off water effect with the underground wall, compares in ordinary drilling row pile, can improve supporting structure's shear strength and security by a wide margin, and the gomphosis structure can avoid producing the phenomenon of relative sliding between underground wall and the pile foundation, and stable in structure is high.

In addition, according to the statistics of drilling holes, in the construction area of the embodiment, the covering layer is deposited surface silt, the layer thickness is 2.00-10.70m, the underlayer rock is strongly weathered argillaceous siltstone, moderately weathered argillaceous siltstone, strongly weathered sandstone and moderately weathered sandstone, the buried depth of the top of the moderately weathered sandstone layer is 11.20-18.00 m, the elevation of the top of the layer is-18.08-11.07 m, and the layer position is relatively stable. Therefore, the pile foundation 1 is embedded into the medium-stroke sandstone to serve as a natural foundation bearing layer of the pile foundation 1, and the depth of the medium-stroke sandstone layer in the embedding of the pile foundation 1 is not less than 5m.

Pile foundation 1 embeds has pile foundation steel reinforcement cage, pile foundation steel reinforcement cage includes two sets of relative arc reinforcing bar sections that set up and connects two sets ofly two sets of splice bar sections of two sections of arc reinforcing bar section, the radian of arc reinforcing bar section with pile foundation 1's radian looks adaptation, and two sections the splice bar section is close to respectively in the guide way setting of pile foundation 1 reservation. The guide way is located pile foundation 1 is along the both sides limit of foundation ditch contour, can make follow-up construction second phase groove 2 be located the tangent line of foundation ditch contour.

This application is through set up the underground wall in second phase groove 2 in order to incite somebody to action 1 connection of pile foundation forms wholly pile foundation 1 with the seam crossing outside of second phase groove 2 department underground wall still spouts the stake in order to form through high pressure rotation and seals the water layer, can further improve this application anchorage supporting construction's waterstop.

In addition, in order to detect pile foundation 1's quality, can be many sounding pipes of ligature on the pile foundation steel reinforcement cage of pile foundation 1 inside, many sounding pipe follows pile foundation steel reinforcement cage's periphery is evenly arranged, sounding pipe's upper end flushes with the pile casing top that construction pile foundation 1 was used, and its lower extreme extends to the pile bottom. The sounding pipe is mainly used as a channel for detecting the depth of the pile foundation 1, extends to the bottom of the pile and can also be used as a channel for grouting the bottom of the pile. The sounding pipe adopts a sectional structure so as to facilitate transportation and construction, and the sectional length of the sounding pipe is consistent with that of the pile foundation reinforcement cage, so that the sounding pipe is bound and fixed when each section of reinforcement cage is constructed conveniently.

The periphery of pile foundation 1 reaches second phase 2 department underground wall still the periphery has laid a plurality of cement stirring stake 3 of interlock each other, cement stirring stake 3 is used as pile foundation 1 reaches the supporting construction of second phase 2 department underground wall. Preferably, the treatment depth of the cement mixing pile 3 in this embodiment reaches the bottom of the sludge layer, so as to reduce the influence of the sludge layer on the deviation, inclination and pile breakage of the pile foundation 1, and improve the overall firmness of the foundation. In the embodiment, the diameter of each cement mixing pile 3 is 60cm, and the meshing range between two adjacent cement mixing piles 3 is 9-11 cm, so that the structural strength between the cement mixing piles 3 is ensured.

Referring to fig. 5, annular crown beams 5 extending along the circumferential direction of the foundation pit are arranged at the tops of the pile foundations 1 and the underground walls at the second-stage groove 2, and the crown beams 5 are connected with all the pile foundations 1 and the underground walls at the second-stage groove 2, so that the integrity of the anchorage supporting structure is improved, the load of the upper structure of the supporting anchorage structure can be supported, distributed and transmitted, and the collapse of the top edge of the foundation pit is prevented.

Further, the inner side of the crown beam 5 is suspended out of the inner side of the underground wall at the pile foundation 1 and the second stage groove 2, and the outer side of the crown beam 5 is flush with the outer side of the underground wall at the pile foundation 1 and the second stage groove 2.

In addition, the anchorage supporting structure of this application still includes the annular access way 4 that is located the foundation ditch outside, annular access way 4 makes things convenient for workman's walking, construction. The bottom of the annular access way 4 is also provided with cement mixing piles 3 which are arranged in a quincunx shape, so that the structural stability of the annular access way 4 is improved.

The filling of the annular sidewalk 4 comprises the following steps: firstly, the access road is dredged by plain filling soil of a soil taking place, then the annular access road 4 is filled by the plain filling soil, and after the annular access road 4 is filled, the annular access road 4 is reinforced by arranging the supporting and stirring piles 41 which are arranged in a quincunx shape. And then, constructing an anchorage supporting structure, and after the construction of the anchorage supporting mechanism is completed, filling an anchorage material storage field 44 by using a strongly weathered argillaceous siltstone layer generated in the anchorage supporting structure, wherein the anchorage material storage field 44 is positioned outside the annular access passage 4 and limited within the range of the access passage.

In addition, the filling construction of the application is carried out according to the roadbed filling track, a road roller is adopted for carrying out layered compaction treatment in the filling process, plastic color strip cloth is required to be adopted for protecting a filling side slope during filling, and the filling soil is prevented from being flushed to the sea due to rising and falling damp. After the filling construction of the annular access way 4 is completed, the access way is further hardened, and the annular access way 4 in the embodiment is hardened and reinforced by adopting a structural form of 15cm water stability and 20cm C20 concrete.

The outside of annular water drain 4 still is equipped with annular escape canal 42, escape canal 42 is connected with sedimentation tank 43, the accessible annular escape canal 42 is with construction water drainage, utilizes sedimentation tank 43 to carry out purification treatment to the construction water to the reduction causes the influence to the environment.

In conclusion, the gravity type anchorage supporting structure for the enclosure of the large-diameter secant pile is adopted, the anchorage foundation is connected by the row piles and the milling joints to form an annular supporting construction scheme, the connection strength between the pile foundations 1 can be improved, the joint water stop effect is good, the gravity type anchorage supporting structure is suitable for construction of the ultra-deep underground diaphragm wall, no lining or support is needed to be additionally arranged in the construction process, the construction period can be shortened, and the construction cost is reduced.

In addition, referring to fig. 6, the construction method of the anchorage support structure specifically includes the following steps:

(1) According to the construction position of the preset boundary pile foundation 1 of the foundation pit to be constructed, the pile foundation 1 is constructed, and guide grooves are preset on the two sides of the pile foundation 1 along the circumferential direction of the foundation pit.

Because the construction region of this application foundation ditch is located coastal limit shoal position, so can be at the foundation ditch department of treating the construction earlier carry out the construction of annular pavement 4, be convenient for constructor to carry out the transportation of construction and construction material, the construction step of annular pavement 4 is seen in detail in the preceding.

After the construction position of the pile foundation 1 is determined according to the preset boundary of the foundation pit to be constructed, the construction area is leveled by using a digging machine, and the construction measurement of the pile foundation 1 is carried out, wherein the construction measurement specifically comprises the construction control of setting out the center position of the pile foundation 1, pile bottom elevation control, hole forming gradient measurement and pile forming acceptance inspection. For example, the lofting of pile central point puts can adopt the polar coordinates method to survey respectively and emit the design vertical axis, the horizontal axis of pile position, and four fender piles are drawn respectively to the central point that crosses pile foundation 1, utilizes four fender piles to carry out pile foundation 1 axes at unscheduled in pile foundation 1 work progress and rechecks to in time discover the off normal and in time rectify a deviation, and carry out the recheck of fender pile with the total powerstation, guarantee each item precision of pile foundation 1 construction.

After the pile position lofting is accomplished in the measurement, carry out the construction of cement mixing pile 3 around pile foundation 1 to as the supporting construction of follow-up construction pile foundation 1 and second phase groove 2 department underground wall, and interlock each other between the adjacent cement mixing pile 3, improve supporting construction's structural strength, prevent the ground water inflow of the process of construction pile foundation 1 and second phase groove 2, can increase the downthehole water pressure of stake, prevent that the hole condition of collapsing from taking place.

When the pile foundation 1 is constructed, the steel casing 11 for pile foundation 1 construction is inserted into the inner side of the cement mixing pile 3 which is finished by construction, and after the deviation of the steel casing 11 is measured and retested to meet the design and standard requirements, the drilling machine can be positioned for operation. In the embodiment, the rotary drilling rig is adopted for drilling, and the stability of the rotary drilling rig must be kept in the construction process. Different drilling buckets are selected according to different geological conditions, particularly for easily drilled bottom layers such as silt, clay and the like, the rotary drilling bucket can be selected as a coating double-bottom bailing bucket, and the teeth of the drilling bucket can be selected as bucket teeth; for coatings which are difficult to drill, such as medium-weathered rock layers and the like, a cylinder drill bit is selected to grind bottom rock, and then a sand bailing bucket is used to fish out drilling slag.

When the rotary drilling rig is used for construction, the abrasion condition of the drill bit is required to be checked frequently, the diameter of the drill bit is measured for multiple times, when the abrasion is serious, the drill bit is repaired immediately in a welding mode, and in addition, the drill bit teeth which are seriously abraded are required to be replaced or repaired in time, so that the smoothness of the drilling process is ensured.

In the drilling process, the control of the drilling rate is also required to be paid attention to, so that the hole collapse and buried drilling accidents caused by too fast footage are avoided, and the lifting rate of the drilling bucket in the embodiment is preferably controlled to be between 0.75 and 0.80 m/s. In the silt layer or the sub-sand layer, the lifting speed is slower; in the stratum with easy diameter shrinkage, the hole sweeping times are properly increased to prevent the diameter shrinkage; drilling the hard plastic layer at a high rotating speed to achieve high drilling efficiency; the sand layer adopts slow speed to drill slowly and increases the specific gravity and viscosity of the mud properly. The drilling operation should be performed continuously without interruption. And when the drilling depth meets the design requirement, retesting the top elevation of the protective cylinder, detecting the final hole depth and the thickness of sediments at the bottom of the hole.

After the pile foundation 1 pore-forming detection is finished, the pile foundation needs to be emptied immediately. The purpose of emptying is to clear away drilling slag and a sediment layer, reduce the sediment thickness at the bottom of a hole as much as possible and prevent the sediment from degrading the bearing capacity of the pile foundation 1 after the pile bottom is left. In the embodiment, the hole cleaning operation adopts a mud replacement mode, diluted high-quality mud flows into the pile hole, and sediment at the bottom of the hole and a drilling slag assembly in the hole are cleaned out of the hole.

During hole cleaning operation, the whole slurry circulating system comprises the following components: mud box → pile hole → sedimentation tank → mud box, the setting of sedimentation tank should not be too little or too big, deposit too slowly when too little, will lengthen the clear hole time. And too big then has increaseed the work load of post processing mud case, clear hole circulation adopts two slush pumps to go on simultaneously to clear hole efficiency improves.

After the clear hole operation of completion, transfer prefabricated pile foundation steel reinforcement cage and concrete pouring pipe in the stake hole, before putting pile foundation steel reinforcement cage under, carry out the laying-out and do the location pile protector according to pile foundation steel reinforcement cage angular point, when putting pile foundation steel reinforcement cage under, utilize the location pile protector reaches the straightness that hangs down that pile foundation steel reinforcement cage transferred is guaranteed to spacing steel box. In addition, limiting steel boxes can be placed in the pile holes along two sides of the preset boundary of the foundation pit, so that guide grooves can be formed in two sides of the pile foundation 1 formed by subsequent pouring.

When the pile foundation reinforcement cage is installed in a downward putting mode, the sounding pipe can be installed correspondingly. The pile foundation steel reinforcement cage in this embodiment divide into the multisection along the direction of height, forms the merogenesis steel reinforcement cage promptly, the sound survey pipe also adopts the form of merogenesis corresponding to pile foundation steel reinforcement cage, and wherein the closed bottom tube of bottom segment steel reinforcement cage sound survey pipe adoption one end, and all the other sound survey pipes adopt a straight tube, and another is welded connection pipe. The lower opening of the sounding pipe is welded and fixed on the pile foundation reinforcement cage, and the rest are used

The reinforcing bars are processed into U-shaped clamping groove structures, and the sounding pipes are welded and fixed on the pile foundation reinforcement cage at intervals of 2 m.

After each section of pile foundation reinforcement cage is in butt joint, the sounding pipes are in butt joint and firmly fixed, the sounding pipes after pile forming are guaranteed to be parallel to each other, water is filled in the sounding pipes to check whether the sounding pipes leak water, the bottoms of the sounding pipes are flush with the bottoms of the pile foundation reinforcement cages, top openings of the sounding pipes are blocked, and the exposed height of top sections of the sounding pipes meets the detection requirements. When each section of reinforcement cage is put down, the sound-measuring pipe is filled with clear water, then the pile foundation reinforcement cage is slightly raised, the water level in the sound-measuring pipe is observed after the sound-measuring pipe is stopped for a period of time, if the water level is not changed, the sound-measuring pipe is compact and leak-free, and then the sound-measuring pipe can be put down after being inserted into the upper and lower sections of sound-measuring pipe by using a sleeve; if the water level drops to some extent, the pile foundation reinforcement cage is required to be lifted slowly, the water leakage position is searched, plugging is carried out, and the lifted pile foundation reinforcement cage can be inserted and lowered after plugging is finished.

After the pile foundation reinforcement cage is completely transferred, the concrete pouring guide pipe is transferred, the concrete pouring guide pipe in the embodiment adopts a special spiral screw thread guide pipe, the spiral screw thread guide pipe adopts a guide pipe with the inner diameter of 360mm, the middle section is 2.5m long, the lowest section is 4-5 m long, and the non-standard sections of 0.5m, 1m and 1.5m are equipped. Before and after the concrete pouring conduit is used, the specification, quality and splicing structure of the concrete pouring conduit are carefully checked, and tests such as splicing, ball passing, watertight, pressure bearing, joint, tensile strength and the like are required. For example, when the water-tight pressure-bearing test is carried out, the water pressure for carrying out the water-tight test is not less than 1.3 times of the water depth in the hole, and is not less than 1.3 times of the maximum internal pressure p when the conduit wall and the welding line can bear poured concrete.

When the concrete pouring guide pipe is watertight and pressure-bearing, a trial assembly test is actually carried out on the concrete pouring guide pipe, the total length of the trial assembly of the concrete pouring guide pipe meets the requirement of pouring concrete on the longest pile, the concrete pouring guide pipe is numbered in sequence from bottom to top, the combination sequence of the guide pipes is strictly kept, the number of the guide pipe is recorded for the guide pipe which is unqualified in watertight test, the guide pipe cannot be used, the axial line of the guide pipe after assembly is poor, and the axial line of the guide pipe cannot exceed 0.5% of the drilling depth and is not more than 10cm.

After the concrete pouring guide pipe is completely placed, constructors adopt the measuring hammer to detect the sediment thickness at the bottom of the hole, and simultaneously detect the performance index of the slurry in the hole again, if the performance index of the slurry does not meet the specification of the slurry and exceeds the specification of the sediment thickness, secondary hole cleaning is carried out. In this embodiment, adopt air compressor machine gas lift reverse circulation to carry out the clear hole of secondary. After the secondary hole cleaning is finished, the air compressor can be dismantled and the underwater concrete begins to be poured through detection of constructors.

The pouring of concrete is divided into first batch concrete pouring and normal concrete pouring, the first batch of concrete adopts a plug pulling method construction process, a small hook of a crane hooks a plug, a big hook hooks a big hopper, after the preparation work is done, the outlet of the big hopper is plugged by the plug, and when the volume of the concrete in the collecting hopper reaches the theoretical first batch concrete pouring volume, the plug in the big hopper is pulled out, so that the concrete falls along the guide pipe. In the whole concrete pouring process, the concrete is continuously poured, so that the first batch of concrete is poured.

And after the first batch of concrete is successfully poured, immediately shifting to a normal pouring stage, conveying the concrete to the pier position through a tank truck, and continuously pouring the concrete into the hole through a large hopper and a guide pipe by a conveying pump until the pouring of the whole pile is completed. During the concrete pouring process, follow-up concrete is slowly poured along the wall of the guide pipe so as to prevent the guide pipe from being blocked due to the formation of a high-pressure air bag in the guide pipe. In addition, in order to ensure the compactness of the foundation concrete of the pile foundation 1, the guide pipe needs to be inserted and shaken regularly, but the lifting amplitude is not too large, so that the effects of vibrating and avoiding pipe sticking are achieved. In the concrete pouring process, water or slurry overflowing from the pile hole is guided to a proper place for treatment and is not discharged randomly.

After the initial setting of the cast-in-place concrete, the limiting steel boxes on two sides of the pile foundation 1 can be pulled out, so that guide grooves for subsequent construction are formed on two sides of the pile foundation 1. After the concrete construction of pile foundation 1 is accomplished and the concrete reaches the detection requirement, can use 1 pore-forming of full-automatic ultrasonic pile foundation to detect pile foundation 1, utilize ultrasonic pulse to pass pile foundation 1 mud and drill hole lateral wall after the part is reflected back to convert the signal of telecommunication into through the receiver and to be exported the operation appearance promptly, according to the strong and weak and reflection time difference of reflected signal, the pore wall curve is drawn in real time to the operation appearance.

(2) And determining the position of a secondary groove 2 between two adjacent pile foundations 1 and excavating.

The position of the second-stage groove 2 is determined according to a design drawing, a guide wall is arranged at the position of the second-stage groove 2 before the second-stage groove 2 is constructed, the notch of the second-stage groove 2 is protected through the guide wall, the accuracy of the groove section position is guaranteed, meanwhile, the guide wall can also be used for supporting construction equipment and lengthening a welding reinforcement cage, the guide wall can be used for adjusting the liquid level in a hole, the construction position is determined, and collapse of the top of the groove wall of the second-stage groove 2 is prevented.

Specifically, the guide wall at each secondary groove 2 includes two L-shaped reinforced concrete walls respectively disposed at two sides of the secondary groove 2 along the predetermined boundary of the foundation pit. When the guide wall is constructed, firstly, the guide wall excavation position is determined according to the axis of the second-stage groove 2 of the pile foundation 1, then the guide wall is excavated by adopting a method combining mechanical excavation and manual correction, the guide wall reinforcing steel bars and the templates are bound during excavation, then concrete pouring is carried out, the guide wall can be demolded after the concrete reaches a certain strength, and meanwhile, the upper surface of the inner wall of the guide wall is supported in a layered mode, so that the guide wall is prevented from being extruded inwards. And after the guide wall template is disassembled and supported, immediately backfilling cohesive soil at the back of the guide wall in a layering manner and compacting.

In addition, the construction joint of the guide wall adopts a closing-up net, steel bar inserting bars are added, the guide wall is integrated, the water seepage situation is reduced, and the construction joint is staggered with the joints of the pile foundation 1 and the secondary groove 2.

And when the construction of the guide wall is finished and the natural maintenance is carried out to over 70 percent of the design strength, the grooving operation of the second-stage groove 2 can be carried out. When the second-stage groove 2 is constructed, a pure milling method and/or a chiseling and milling method can be adopted for excavating.

Wherein, the pure milling method adopts grab milling to form a groove, and when an upper sludge stratum is constructed, a rope grab bucket is adopted to open a hole; and when the lower part of the construction is strong to medium weathered rock, a groove milling machine is used for milling the groove. And the drilling and milling method is used for replacing the standard wheel of the slot milling machine with a cone wheel through the drilling and milling method under the condition of high rock strength, and adopting a steel wire rope crane heavy chisel to match with the slot milling machine for excavation.

When the slot milling machine is used for milling the second-stage slot 2, a guide frame must be used to ensure the accurate positioning of the second-stage slot 2 in the slot forming process. The precision of the second-stage groove 2 is required to be ensured in the grooving process, and construction workers can perform preliminary judgment through a visual method, so that the deviation of the groove section excavation verticality is within the maximum allowable value range. Meanwhile, a deviation correcting device is arranged on the slot milling machine, deviation can be corrected along with digging, the perpendicularity of a formed slot is ensured, the deviation condition is reflected to a computer connected in a cab through a probe line at any time according to the probe arranged on the hydraulic slot milling machine, a driver can start a hydraulic push plate on the hydraulic slot milling machine to dynamically correct the deviation according to dynamic deviation conditions in four directions on the computer, and accurate dynamic deviation correction is continuously carried out in the forming slot, so that the requirement on the vertical precision of a second-stage slot 2 is ensured. In addition, the stress state of the steel wire rope is kept during groove milling, and the precision is convenient to control.

After the second-stage groove 2 is milled, the second-stage groove 2 is cleaned and slurry is changed by using a suction pump method of the groove milling machine and a slurry separation system of the groove milling machine, a milling head of the groove milling machine is arranged at the bottom of the second-stage groove 2, a milling wheel is kept to rotate, a slurry pump in the milling head conveys slurry at the bottom of the groove to a slurry separator on the ground, large-particle drilling slag is removed by a vibrating screen of the slurry separator, the slurry enters a cyclone to separate fine powder and sand in the slurry, the purified slurry flows back into the second-stage groove 2, and the steps are repeated in a circulating mode to complete replacement of the slurry in the second-stage groove 2.

In the process of changing slurry and recovering slurry, a slurry separation system is required to separate the recovered slurry, the separated slurry is detected, the qualified slurry is continuously recycled, and the unqualified slurry is discarded.

In addition, in order to improve the anti-permeability and anti-shearing performance of the joint, before the hole cleaning of the secondary slot 2, wall brushing cleaning is carried out on the slot wall of the guide slot of the pile foundation 1.

(3) And constructing underground walls at the secondary slots 2 to connect the adjacent pile foundations 1 into a whole.

Firstly, hoisting a prefabricated underground wall reinforcement cage, and ensuring the downward verticality of the underground wall reinforcement cage. And for preventing that underground wall steel reinforcement cage from taking place too big bending deformation when lifting by crane, this application adopts a main crawler crane and an auxiliary crawler crane cooperation hoist and mount operation. Specifically, the main crawler crane and the auxiliary crawler crane are commanded to horizontally hoist the underground wall reinforcement cage to be lowered at the same time, after the underground wall reinforcement cage is hoisted to a distance of 0.3-0.5 m from the ground, the main crawler crane lifts the hook upwards, and then the auxiliary crawler crane is commanded to be matched with the hook according to the distance between the tail part of the underground wall reinforcement cage and the ground. After the reinforcing cage of the underground wall falls, the main crawler crane rotates leftwards (or rightwards), and the auxiliary crawler crane rotates forwards to a proper position so that the reinforcing cage of the underground wall is gradually vertical to the ground. When the underground wall reinforcement cage is completely vertical to the ground and is stable, a crane worker can operate and control the auxiliary crawler crane on the underground wall reinforcement cage, and then direct the main crawler crane to hoist the underground wall reinforcement cage to be inserted into the secondary slot 2. When the reinforcement cage is inserted, the center of the lifting point must be aligned with the center of the secondary slot 2, and then the reinforcement cage is slowly descended to be vertically and accurately lifted into the slot. Care must be taken not to cause the cage to sway laterally due to boom sway or other effects, causing the walls of the trough to collapse.

Underground wall steel reinforcement cage hoisting point arranges and lifts by crane the mode and arouses the deformation of steel reinforcement cage when will preventing to lift by crane, can not make the steel reinforcement cage lower extreme drag subaerial when lifting by crane in order to cause lower extreme reinforcing bar bending deformation, prevents simultaneously that the steel reinforcement cage from taking place the swing in the air after lifting by crane, will drag the messenger rope with the manual operation on the system of steel reinforcement cage lower extreme.

And after the underground wall reinforcement cage is installed, a second-stage groove perfusion guide pipe is installed, and the placement center of the second-stage groove perfusion guide pipe and the center of the pile foundation 1 are on the same line. The installed secondary slot perfusion conduit can also be used for secondary hole cleaning of the secondary slot 2, and indexes such as hole depth and the like are detected after hole cleaning is finished.

The concrete pouring of the underground wall of the second-stage groove 2 adopts the matching of a large hopper and a small hopper, and the concrete of the underground wall at the second-stage groove 2 is also divided into the first-batch concrete pouring and the normal concrete pouring.

Specifically, the first batch of concrete is directly conveyed to the large hopper by the tank car, and after the large hopper is filled with the concrete, the concrete is simultaneously poured when the other tank car is replaced and the large hopper is used for discharging. The orifice hopper is sealed by a manual valve, namely, a valve is arranged at the bottom of the hopper and above the top opening of the guide pipe to seal the guide pipe opening. The valve extends out by welding the steel bars, and the valve can be manually opened when the first batch of concrete is poured, so that the concrete can naturally fall. After the large hopper is filled with concrete, the concrete is primarily filled, the manual valve switch of the large hopper is rapidly opened, so that the concrete is continuously filled into the hole bottom from the chute to the orifice hopper along the guide pipe, and meanwhile, the tank car continuously replenishes the concrete in the large hopper, thereby completing the filling of the first batch of concrete.

After the first batch of concrete is poured, the small hopper is replaced immediately for normal concrete pouring, so that the concrete is poured through the small hopper and the second-stage groove pouring guide pipe. In the concrete pouring process, the second-stage groove pouring guide pipe needs to be continuously removed, specifically, a pouring frame is arranged in the embodiment, the second-stage groove pouring guide pipe can be conveniently lifted and removed through the pouring frame, the burial depth of the second-stage groove pouring guide pipe is controlled to be 2-6 m during pouring, and after the second-stage groove pouring guide pipe is removed every time, the bottom opening burying depth of the second-stage groove pouring guide pipe is not less than 2m and not more than 6m at most.

And then, carrying out water sealing and reinforcing treatment on the underground walls at the pile foundation 1 and the second-stage groove 2 after construction, and specifically adopting a high-pressure jet grouting pile to spray and grout the outer sides of the underground walls at the pile foundation 1 and the second-stage groove 2 to form a reinforcing waterproof layer.

Specifically, the high-pressure jet grouting pile can be constructed when the strength of the underground wall at the pile foundation 1 and the secondary trough 2 reaches 80%, the reinforcing position of the high-pressure jet grouting pile in the embodiment is 0.3-0.4 m outside the joint of the pile foundation 1 and the underground wall, and the reinforcing range is 2-23.1 m. And the construction of the high-pressure rotary jet grouting pile adopts a single-pipe method, the air pressure is not less than 0.7MPa, the hydraulic pressure of cement paste is not less than 20MPa, and the rotary jet grouting lifting speed is 15-25 cm/min. When the grouting pipe is placed into the drill hole, the nozzle reaches the designed elevation to spray grouting, and after the spraying grouting parameters reach the specified values, the grouting pipe is lifted according to the process requirements of the jet grouting pile, and the grouting is sprayed from bottom to top. The rotating speed of the drill rod in the lifting process is 15-20 r/min, and the overlapping length of the sectional lifting of the grouting pipe is preferably more than 300mm.

(4) Repeating the steps until the construction of all the pile foundations 1, the second-stage groove 2 and the underground wall is completed;

(5) And constructing a crown beam 5 on the top of the underground wall at the constructed pile foundation 1 and the second-stage groove 2.

This application is through constructing crown beam 5 in order to connect whole pile foundation 1 and 2 underground walls in second phase groove and form wholly, equally divide crown beam 5 planes in this embodiment into 4 length units and construct, and set up the post-cast section between every length unit, then this application construction crown beam 5 includes following step:

firstly, after the construction of underground walls at all pile foundations 1 and secondary tanks 2 is complete and the concrete reaches 80% of the design strength, the inner guide wall is dismantled in sections, the guide wall concrete can be broken by a backhoe and hydraulic bubbles, and the guide wall concrete is transported to a designated place for treatment by a backhoe crash.

After the guide wall is removed, a construction route for excavating the crown beam 5 foundation pit can be determined according to a design drawing, and the crown beam 5 foundation pit is excavated along the circular arc symmetry from the axis of the bridge according to the construction route. Crown 5 foundation pits of roof beam and adopt and put the slope excavation, the excavation slope of this embodiment is 1 to chisel out the super-filled concrete of 2 underground walls in groove 2 to pile foundation 1 and second phase, expose fresh concrete face and crown 5 structures of roof beam, with the integrality that keeps pile foundation 1 and second phase 2 underground wall tops of groove.

And then, installing a template and an embedded part of the crown beam 5 at the position of a foundation pit of the crown beam 5, wherein the template of the crown beam 5 comprises a side template and an end template, the bottom template of the crown beam 5 adopts a concrete hardened layer at the top of the underground wall of the pile foundation 1 and the secondary trough 2, the side template adopts a large qualitative steel template, and the end template adopts a closing-up net non-dismantling template. The embedded parts comprise loose cable saddle foundation and anchor block connecting bars, ladder stand installation embedded parts, anti-segregation conduit bracket and operating platform embedded parts, foundation pit construction water supply pipe embedded parts and foundation pit safety protection railing embedded parts.

Then, according to the sequence of the soil body excavation of the crown beam 5, the crown beam 5 is symmetrically poured along the circular arc, and finally, the post-pouring section is poured, so that the construction of the crown beam 5 is completed.

The construction method of the anchorage supporting structure has simple steps, no lining and support are required to be additionally applied in the construction process, the construction period is shortened to a great extent, and the construction cost is reduced; the construction of the access road is carried out before the construction, the construction of workers and the storage of materials are facilitated, and the construction efficiency is greatly improved. The foregoing is only a few embodiments of the present application and it should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present application, and that these improvements and modifications should also be considered as the protection scope of the present application.

Claims (11)

1. The construction method of the anchorage supporting structure is characterized in that the anchorage supporting structure comprises a pile foundation and a second-stage groove section wall, the pile foundation and the second-stage groove section wall are arranged along the periphery of a foundation pit at intervals, and all the pile foundations are connected into a whole through the second-stage groove section wall, and the construction method comprises the following steps:

(1) According to the construction position of a pile foundation at a preset boundary of a foundation pit to be constructed, constructing the pile foundation, reserving guide grooves for providing a guide effect for the excavation of a second-stage groove on two sides of each pile foundation along the contour of the preset boundary of the foundation pit, wherein the guide grooves are communicated with the second-stage groove, so that an underground wall constructed in the second-stage groove subsequently is embedded with the pile foundation connected with the underground wall;

(2) Determining the position of a second-stage groove between two adjacent pile foundations and excavating;

(3) Constructing an underground wall at a second-stage groove to connect adjacent pile foundations to form a whole, and excavating the second-stage groove by adopting a pure milling method and/or a chiseling and milling method, wherein the pure milling method adopts grabbing and milling to form the groove, when a sludge stratum at the upper part is constructed, a rope grab bucket is adopted to open a hole, when a rock is strongly gasified in the lower part of the construction, the groove is milled by using a groove milling machine, the chiseling and milling method is used for replacing a standard wheel of the groove milling machine with a cone pulley under the condition that the rock strength is high, and a steel wire rope crane heavy chisel is adopted to cooperate with the groove milling machine to excavate;

(4) Repeating the steps until the construction of all pile foundations, the secondary trough and the underground wall is completed;

(5) Constructing a crown beam on the top of the constructed pile foundation and the underground wall at the second-stage groove;

in addition, before the construction of the step (3), guide walls are preset at the construction positions of the second-stage grooves, the guide walls at the positions of the second-stage grooves comprise two L-shaped reinforced concrete walls which are respectively arranged at two sides of the second-stage grooves along the preset boundary of the foundation pit, and when the concrete strength of the guide walls reaches more than 70% of the design strength, the second-stage grooves can be excavated.

2. The construction method of an anchor support structure according to claim 1, further comprising a step of constructing cement mixing piles in the circumferential direction of the pile foundation before constructing the pile foundation, adjacent cement mixing piles being engaged with each other.

3. The construction method of an anchorage support structure according to claim 2, wherein the construction of the pile foundation in step (2) includes the steps of:

inserting and driving a steel pile casing on the inner side of the cement mixing pile, and excavating and forming holes by using a drilling machine;

putting down a prefabricated pile foundation reinforcement cage and a concrete pouring guide pipe;

and (5) utilizing the concrete pouring guide pipe to pour the pile foundation concrete, and finishing the construction of the pile foundation.

4. The construction method of an anchorage support structure according to claim 3, characterized in that after the drilling machine excavates a hole, the height of the top of the steel casing, the depth of the pile foundation hole, the thickness of the sediment at the bottom of the hole, the hole diameter of the pile foundation hole and the verticality of the pile foundation are detected;

and cleaning the pile foundation hole after the detection is finished so as to remove the drilling slag and the precipitation layer in the pile foundation hole.

5. The construction method of an anchorage support structure according to claim 3, characterized in that, before the pile foundation reinforcement cage is lowered, limiting steel boxes are correspondingly inserted into both sides of the steel casing to reserve guide grooves on the pile foundation; and after the concrete of the pile foundation is initially set, pulling out the limiting steel box.

6. The construction method of an anchorage support structure according to claim 5, characterized in that before a pile foundation reinforcement cage is laid down, lofting is performed according to reinforcement cage corner points and positioning guard piles are made;

when the pile foundation steel reinforcement cage is transferred, the verticality of the transfer of the pile foundation steel reinforcement cage is ensured by utilizing the positioning pile protection and the limiting steel box.

7. The construction method of the anchorage supporting structure according to claim 1, characterized in that after the second-stage groove is milled, the groove milling machine and a slurry separation system thereof are used for hole cleaning and slurry changing of the second-stage groove by an air suction pump method, a milling head of the groove milling machine is placed at the bottom of the second-stage groove and a milling wheel is kept rotating, a slurry pump in the milling head conveys slurry at the bottom of the groove to a slurry separator on the ground, large-particle drilling slag is removed by a vibrating screen of the slurry separator, the slurry enters a cyclone to separate fine powder sand in the slurry, the purified slurry flows back to the second-stage groove, and the process is repeated in a circulating manner to complete the slurry replacement in the second-stage groove.

8. The construction method of an anchorage support structure according to claim 1, wherein the construction of the second-stage groove section wall in step (4) comprises the steps of:

hoisting a prefabricated second-stage groove steel reinforcement cage, and ensuring the downward verticality of the second-stage groove steel reinforcement cage;

placing a second-stage groove pouring guide pipe, wherein the placing center of the second-stage groove pouring guide pipe and the center of the pile foundation are positioned on the same line, and cleaning the second-stage groove by using the second-stage groove pouring guide pipe before pouring concrete;

the concrete is poured to form the underground wall to connect the adjacent pile foundations into a whole.

9. The construction method of an anchorage support structure according to claim 8, wherein the pouring of concrete to form the underground wall at the secondary trough comprises the steps of:

the large hopper is utilized for primary concrete pouring, the large hopper is filled with concrete, then a valve switch of the large hopper is opened, the concrete is poured into the hole bottom along a second-stage groove pouring guide pipe, and the concrete tank truck continuously replenishes the concrete into the large hopper at the same time until the first batch of concrete is poured;

and replacing the large hopper with a small hopper, arranging a pouring frame, pouring concrete through the small hopper and the second-stage groove pouring guide pipe, and lifting and removing the second-stage groove pouring guide pipe through the pouring frame when the embedding depth of the second-stage groove pouring guide pipe exceeds 6m until the pouring of all the concrete is completed.

10. The construction method of the anchorage supporting structure according to claim 1, wherein after the construction of the pile foundation and the underground wall at the second stage groove is completed, the outer side of the joint between the pile foundation and the underground wall at the second stage groove is treated by high-pressure rotary pile-spraying to seal water.

11. The construction method of an anchorage support structure according to claim 1, wherein the crown beam is divided into four length units for construction, and a post-cast section is provided between two adjacent units, and the construction of the crown beam comprises the steps of:

excavating a crown beam foundation pit at the tops of the pile foundation and the underground wall at the secondary groove, wherein the crown beam foundation pit is excavated by slope excavation;

chiseling the super-poured concrete of the pile foundation and the underground wall at the secondary trough to expose a fresh concrete surface;

installing a crown beam template and an embedded part, wherein the crown beam template comprises a side mold and an end mold, and the embedded part comprises a connecting rib of a cable saddle foundation and an anchor block, a ladder stand installation embedded part, an anti-segregation guide pipe bracket, an operation platform embedded part, a foundation pit construction water supply pipe embedded part and a foundation pit safety protection railing embedded part;

and symmetrically pouring the length units of the crown beam along the circular arc, and finally pouring a post-pouring section to connect the four length units to form the integral crown beam.

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