CN111173049A - Experimental device for be used for simulating following with boring pipe stake pile side slip casting - Google Patents
Experimental device for be used for simulating following with boring pipe stake pile side slip casting Download PDFInfo
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- CN111173049A CN111173049A CN201911393033.6A CN201911393033A CN111173049A CN 111173049 A CN111173049 A CN 111173049A CN 201911393033 A CN201911393033 A CN 201911393033A CN 111173049 A CN111173049 A CN 111173049A
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- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
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Abstract
The invention belongs to the technical field of geotechnical engineering pile foundation model tests, and particularly discloses an experimental device for simulating pile side grouting of a pipe pile while drilling, which comprises a model box system, a loading system, a water supply system and a grouting system; the model box system comprises a model box, a grout stopping plate, a model pile with a sealed bottom end and a hole forming barrel with the diameter larger than that of the model pile; the loading system comprises a confining pressure dividing device, an axial pressure dividing device and a plurality of strain gauges; the water outlet of the water supply system is communicated with the water inlet of the tank; and a grout outlet of the grouting system is communicated with the grouting hole. According to the invention, the loading system is arranged to simulate the earthing pressure, the water supply system is used to simulate the underground flowing water, the grouting parameters of the grouting system are adjusted, so that grouting bodies under different grouting technological parameters can be obtained, the relation curve between the pressure applied to the model pile by the loading system and the displacement of the strain gauge is obtained, the bearing capacity and the side friction force of the pile along with drilling can be calculated, and the grouting effect can be judged.
Description
Technical Field
The invention belongs to the technical field of geotechnical engineering pile foundation model tests, and particularly relates to an experimental device for simulating pile side grouting of a pipe-following pile while drilling.
Background
The pile foundation plays an irreplaceable role in the rapid advance of the urbanization process as the foundation of high-rise construction, and the economic and environment-friendly high-strength concrete tubular pile (PHC tubular pile) overcomes the problems that the traditional steel pile is high in cost and poor in corrosion resistance, the pile quality of a drilled (punched) hole cast-in-place pile is difficult to control, the pile is easy to collapse, a large amount of slurry is generated in construction, environmental pollution is easily caused and the like, but the conventional pile sinking method of the PHC tubular pile mainly adopts a static pressure method and a hammering method, the pile sinking resistance is large, the pile body is easy to damage and noise pollution are easily caused, and the application range of the high-strength PHC tubular pile is limited (the general application diameter is 300mm to 600mm, and the high-strength PHC tubular pile is generally suitable for a.
A Pile driver with a Pipe and a construction method (ZL201210022133.X) of the Pile driver with the Pipe solve the problems, the Pile driver with the PHC Pipe cast Pile, DPC Pile for short, is a non-soil-squeezing large-diameter PHC Pipe Pile foundation (the diameter is 800-1400 mm) with the functions of Drilling, Pile sinking and soil discharging, the radius of the drilled hole is about 10mm larger than that of the Pipe Pile, the Pipe wall and the soil around the Pile cannot be in direct contact, and the Pile foundation is filled by means of subsequent pouring of cement slurry or cement mortar to improve the side friction resistance of the Pile, so that the bearing capacity is improved, and the grouting effect is a key factor of the bearing capacity and the seismic resistance of the Pile foundation. The optimization of the grouting process plays a decisive role in the grouting effect, and finally influences the exertion of the frictional resistance on the side of the DPC pile, but the optimization of the grouting process by carrying out a large-scale grouting test on site is not practical, so that the development of a physical simulation test for optimizing the DPC pile side grouting process is very important.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides an experimental device for simulating pile side grouting of a pipe-following pile while drilling, which can simulate a real stratum environment so as to test the influence of different grouting process parameters on a grouting effect.
In order to achieve the purpose, the invention adopts the following technical scheme:
an experimental device for simulating pile side grouting of a pipe-following pile while drilling comprises a model box system, a loading system, a water supply system and a grouting system; the model box system comprises a model box, a grout stopping plate and a model pile with a sealed bottom end; a plurality of tank water inlets and tank water outlets are formed in the side wall of the model tank, and the water outlet of the water supply system is communicated with the tank water inlets; soil is filled in the model box, a simulated drilling hole is formed in the soil, and the diameter of the simulated drilling hole is larger than that of the model pile; the model pile is coaxially arranged in the simulated drilling hole, a plurality of grouting holes for grouting the gap are formed in the model pile, and a grouting outlet of the grouting system is communicated with the grouting holes; the grout stopping plate is provided with a through hole matched with the model pile, and the grout stopping plate is sleeved at the upper end of the model pile through the through hole so as to seal a gap between the model pile and the soil body;
the loading system comprises a confining pressure dividing device for applying pressure to the soil body, an axial pressure dividing device for applying pressure to the model pile and a plurality of strain gauges; the confining pressure separating device is arranged at the top end of the model box and located on two sides of the model pile, the axial pressure separating device is arranged at the top end of the model pile, and the strain gauge is attached to the outer side wall of the model pile.
Compared with the prior art, the method has the advantages that the model box system is arranged to set up the pile side grouting site of the follow-up pipe pile while drilling, the loading system is arranged to simulate the earthing pressure, the water supply system is used to simulate the underground running water, different pressures applied by the loading system and the water supply pressure provided by the water supply system can simulate the formation environment more truly, the grouting parameters of the grouting system are adjusted, the grouting bodies under different grouting process parameters can be obtained, the relation curve between the pressure applied by the loading system on the model pile and the pile body strain of the model pile acquired by the strain gauge is obtained, the bearing capacity and the frictional resistance of the follow-up pipe pile while drilling can be calculated, and the grouting effect can be judged.
Preferably, the grouting system comprises a slurry storage tank and a grouting machine for injecting slurry in the slurry storage tank into the gap; the grouting device is characterized by further comprising a control valve, wherein the control valve is arranged on the grouting pipe communicated with the grouting hole and the outlet of the grout storage pool.
Preferably, the grouting system further comprises a pressure regulating valve and a pressure gauge, the pressure regulating valve is arranged on the grouting pipe between the grout storage tank and the control valve, and the pressure gauge is arranged on the grouting pipe between the pressure regulating valve and the control valve.
Preferably, the loading system further comprises a first pressure detector for detecting a pressure value in the soil body and a second pressure detector for detecting a pressure value loaded on the model pile, the first pressure detector is arranged at the upper end and the lower end of the soil body and is opposite to the confining pressure separation device, and the second pressure detector is arranged at the top end and the bottom end of the model pile and is opposite to the shaft pressure separation device.
Preferably, a sensing hole is formed in a bottom plate of the model box, a sensing pad is arranged below the bottom plate of the model box, and the second pressure detector is arranged on the sensing pad and located in the sensing hole.
Preferably, the loading system further comprises a reaction frame, the confining pressure separation device comprises a first jack, the shaft pressure separation device comprises a second jack, the reaction frame is arranged at the top end of the model box, two ends of the first jack are respectively abutted to the reaction frame and the model box, and two ends of the second jack are respectively abutted to the reaction frame and the model box.
Preferably, the model pile comprises a plurality of model piles, and the number of the grouting holes on each model pile is different, or the hole diameter is different, or the distance from the top end of the model pile is different.
Preferably, the pore-forming barrel comprises a plurality of pore-forming barrels, and the diameter of each pore-forming barrel is different.
Preferably, the grout stop plate comprises a first sub-plate and a second sub-plate, the first sub-plate is provided with a first semicircular arc, the first sub-plate is located on the first sub-plate, first threaded holes are formed in two sides of the first semicircular arc, the second sub-plate corresponds to the first semicircular arc and the first threaded holes and is provided with a second semicircular arc and a second threaded hole, and the first sub-plate and the second sub-plate are fixed on the model pile through bolts.
Preferably, a permeable stone layer is uniformly paved between the side wall of the model box and the soil body.
Drawings
The invention will now be further described with reference to the accompanying drawings and specific embodiments thereof:
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a schematic view of the structure of the bottom plate of the mold box of the present invention;
FIG. 3 is a schematic view of the construction of the side panels of the mold box of the present invention;
FIG. 4 is a schematic view of the construction of a model pile and a grout pipe according to the present invention;
FIG. 5 is a schematic structural view of the vented cartridge of the present invention;
FIG. 6 is a schematic structural view of the grout stop plate of the present invention.
In the figure:
1. grouting machine, 2, slurry storage tank, 3, pressure regulating valve, 4, pressure gauge, 5, control valve, 6, grouting pipe, 7, first jack, 8, upper pressure sensor, 9, reaction frame, 10, second jack, 11, upper soil pressure box, 12, slurry stopping plate, 13, box water outlet, 14, model pile, 15, gap, 16, slurry diffusion track, 17, lower grouting hole, 18, lower soil pressure box, 19, bottom plate, 20, foam pad, 21, lower pressure sensor, 22, side plate, 23, concrete seal, 24, middle grouting hole, 25, grouting body, 26, soil body, 27, cobble layer, 28, strain gauge, 29, box water inlet, 30, sensing hole, 31, pore-forming barrel, 32, long screw, 33, screw hole, 34, semi-circular hole.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
As shown in fig. 1 to 6, the present embodiment discloses an experimental apparatus for simulating pile side grouting of a pipe-following pile while drilling, including a mold box system, a loading system, a water supply system, and a grouting system; the model box system comprises a model box, a slurry stop plate 12 and a model pile 14 with a sealed bottom end; a plurality of tank water inlets 29 and tank water outlets 13 are formed in the side wall of the model tank, and a water outlet of the water supply system is communicated with the tank water inlets 29; the model box is filled with soil 22, a simulated borehole is arranged in the soil 22, and the diameter of the simulated borehole is larger than that of the model pile 14; the model pile 14 is coaxially arranged in the simulated drilling hole, and a plurality of grouting holes for grouting the gap 15 are formed in the model pile 14; the grout outlet of the grouting system is communicated with the grouting hole; the grout stopping plate 12 is provided with a through hole matched with the model pile 14, and the grout stopping plate 12 is sleeved at the upper end of the model pile 14 through the through hole to seal a gap 15 between the model pile 14 and the soil body 26; the loading system comprises a confining pressure separation device for applying pressure to the soil body 26, an axial pressure separation device for applying pressure to the model pile 14, and a plurality of strain gauges 28; the confining pressure separating device is arranged at the top end of the model box and located on two sides of the model pile 14, the axial pressure separating device is arranged at the top end of the model pile 14, and the strain gauge 28 is attached to the outer side wall of the model pile 14.
The grouting system comprises a slurry storage tank 2, a grouting machine 1 for injecting slurry in the slurry storage tank 2 into the gap 15, a control valve 5, a pressure regulating valve 3 and a pressure gauge 4; the control valve 5 is arranged on a grouting pipe 6 which is communicated with the grouting hole at the outlet of the slurry storage tank 2, the pressure regulating valve 3 is arranged on the grouting pipe 6 between the slurry storage tank 2 and the control valve 5, and the pressure gauge 4 is arranged on the grouting pipe 6 between the pressure regulating valve 3 and the control valve 5; the grouting machine 1 is preferably an air compressor;
in this embodiment, a hole forming barrel 31 with a diameter larger than that of the model pile 14 is further included; the model box is filled with soil 26, and when the model box is filled with soil, the hole forming barrel 31 is arranged in the model box so that the simulated drilled holes are formed in the soil 26 when the hole forming barrel 31 is pulled away;
the model piles 14 comprise a plurality of model piles, and the diameter of the grouting holes on each model pile 14 is different or the distance from the top end of each model pile 14 is different; the hole forming barrel 31 comprises a plurality of holes, and the diameter of each hole forming barrel 31 is different;
in this embodiment, a sealing ring is disposed between the grout stopping plate 12 and the model pile 14, and a plurality of fine pinhole-shaped micropores are disposed on the sealing ring, and the pinhole-shaped micropores can discharge air in the gap during grouting and suppress the pressure of the grout.
Compared with the prior art, the method has the advantages that the model box system is arranged to set up the pile side grouting site of the pipe-following pile while drilling, the loading system is arranged to simulate the earthing pressure, the water supply system is used to simulate the underground running water, and different pressures applied by the loading system and the water supply pressure provided by the water supply system can simulate the stratum environment more truly; in the embodiment, the pressure of grouting is adjusted through the pressure adjusting valve 3, the pressure gauge 4 and the grout stopping plate 12; the control valve 5 is controlled to be normally opened or switched on and off at a certain frequency so as to simulate static pressure grouting, pulsating grouting and the like; and further, the grouting parameters of the grouting system are adjusted, the grouting body 25 under different grouting process parameters is obtained, the relation curve of the pressure applied to the model pile 14 by the loading system and the pile body strain of the model pile 14 acquired by the strain gauge 28 is obtained, the bearing capacity and the frictional resistance of the pipe pile while drilling can be calculated, and the grouting effect is judged.
In this embodiment, the loading system further includes a first pressure detector for detecting a pressure value in the soil 26 and a second pressure detector for detecting a pressure value loaded on the model pile 14, the first pressure detector is disposed at the upper end and the lower end of the soil 26 and faces the confining pressure sub-device, and the second pressure detector is disposed at the top end and the bottom end of the model pile 14 and faces the axial pressure sub-device.
In this embodiment, loading system still includes reaction frame 9, confining pressure partial shipment is put including first jack 7, axle pressure partial shipment is put including second jack 10, reaction frame 9 sets up the top of mold box, the both ends of first jack 7 butt respectively reaction frame 9 with the mold box, the both ends of second jack 10 butt respectively reaction frame 9 with the mold box. Wherein, the first jack 7 and the second jack 10 are both high-precision jacks.
In this embodiment, the first pressure detector is a pressure box, the second pressure detector is a pressure sensor, and the pressure boxes are respectively arranged in the upper soil 26 and the lower soil 26 of the model box and face the first jack 7; a sensing hole 30 is arranged on the bottom plate 19 of the model box, a sensing pad is arranged under the bottom plate 19 of the model box, the second pressure detector is arranged on the sensing pad and positioned in the sensing hole 30, and the second pressure detector is also arranged between the second jack 10 and the model pile 14. The sensing mat is preferably a circular foam mat 20 and the second pressure detector is preferably a circular pressure sensor.
In this embodiment, a layer of permeable stone is uniformly laid between the sidewall of the mold box and the soil 26, and further, the layer of permeable stone is a layer of cobblestones 27.
In this embodiment, the grout stop plate 12 comprises a first sub-plate and a second sub-plate, the first sub-plate is provided with a first semicircular arc, the first sub-plate is provided with first threaded holes in two sides of the first semicircular arc, the second sub-plate is provided with a second semicircular arc and a second threaded hole in correspondence with the first semicircular arc and the first threaded holes respectively, and the first sub-plate and the second sub-plate are fixed on the model pile 14 through bolts.
The mold box in this embodiment is rectangular, the length, width and height are 1m, 1m and 1.2m, respectively, the bottom of the mold box is a 3cm thick steel plate, i.e., a bottom plate 19, a sensing hole 30 with a diameter of 22cm is drilled in the center of the bottom plate 19 so as to place a circular foam pad 20 and a circular pressure sensor (i.e., a lower pressure sensor 21);
the periphery of the model box is composed of 4 steel plates with the thickness of 3cm, namely four side plates 22, 6 box water outlets 13/box water inlets 29 with the diameter of 3cm are symmetrically arranged on each side plate 22, a layer of cobble layer 27 with the thickness of 3-5cm and the diameter of 1-2cm is paved along the side plates 22 on the periphery in the model box so as to uniformly disperse the water pressure of the box water inlets 29 and the box water outlets 13 and simulate the water flow speed in a real stratum by adjusting the water pressure at the box water inlets 29;
the top of the model box is provided with a cross reaction frame 9 so as to be matched with a first jack 7 to apply axial reverse load, and the size of the reverse load is controlled to simulate the soil covering pressure of different depth strata;
the model pile 14 is a polyvinyl chloride pipe (namely, a polyvinyl chloride pipe for short) with the outer diameter of 18cm and the inner diameter of 16cm, the length of the pipe is 0.8m, round holes (the diameter of the round hole is 1-3cm) are drilled at different positions on the pile side of the model pile 14 to simulate a grouting hole, silicone tubes with the same diameter as the grouting hole are respectively placed from the pile core of the model pile 14, the silicone tubes are bonded with the grouting hole to simulate the grouting pipe 6, and the number, the diameter and the position of grout outlets in the real grouting process are simulated by changing the diameter, the number and the position of the grouting holes;
strain gauges 28 (type is preferably 120-1AA strain gauge) are attached to the positions, 0cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm and 80cm away from the lower end of the model pile 14, the circular foam and the circular pressure sensor are placed in a circular hole, 22cm, at the bottom of the model box, carrying out layered compaction filling in the model box, after the filling thickness reaches 10cm, symmetrically arranging two lower soil pressure boxes 18 at positions respectively 25cm and 30cm away from the side edge of the model box, so as to measure the pressure of the soil body 26 at the bottom position conveniently at the later stage, then the pore-forming barrel 31 (with the diameter of 18-20cm) is placed right above the lower pressure sensor 21, the soil is filled continuously, after the soil filling thickness reaches 80cm, two lower soil pressure boxes 18 are symmetrically arranged at positions 25cm and 30cm away from the side edge of the model box in the same manner, so that the pressure of the soil body 26 at the upper part of the soil body 26 can be conveniently measured at the later stage;
the hole forming barrel 31 is pulled out, so that a simulated borehole with the diameter of 18-20cm is formed in the soil body 26, then the model pile 14 (with the diameter of 18cm) is placed in the simulated borehole, and the distance between the model pile 14 and the soil body 26 in the hole can be realized to be 0-10mm by changing the diameter of the hole forming barrel 31, so that the hole shrinkage phenomenon caused by lateral soil pressure can be simulated;
connecting a grout stopping plate 12 at a position 10cm away from the top end of a pile body, then continuously filling soil, stopping filling the soil after the total thickness of the filled soil reaches 88cm, wherein the grout stopping plate 12 consists of two steel plates with the length, width and height of 40cm, 20cm and 2cm respectively, a semicircular hole 34 with the diameter of 18.2cm is drilled on one side of each steel plate with the side length of 40cm and is slightly larger than the diameter (18cm) of the model pile 14, a sealing ring is adopted for sealing between the circular hole and the model pile 14, and a plurality of fine pinhole-shaped micropores are formed in the sealing ring so as to discharge air during grouting and suppress cement grout to simulate different grouting pressure effects;
after the soil filling work is finished, applying load through a cross reaction frame 9 and a first jack 7 at the top, and controlling the load size through the readings of an upper soil pressure box 11 and a lower soil pressure box 18 so as to simulate the soil covering pressure of different depth strata; water flows with different pressures and flow rates are provided through a plurality of tank water inlets 29 and tank water outlets 13 arranged on the side wall of the model tank and the water supply system so as to simulate the water environment in the stratum;
the grouting pipe 6 is externally connected with a control valve 5, a pressure gauge 4, a pressure regulating valve 3, a slurry storage tank 2 and an air compressor, pressure is provided by the air compressor for grouting, the grouting pressure is controlled by the pressure regulating valve 3 to simulate a static pressure grouting process, and the grouting frequency is simulated by regulating and controlling the opening and closing frequency of the control valve 5 to realize a simulated pulsation grouting process; after the grout is completely solidified, a round upper pressure sensor 8 is placed on the pile top, an axial load is applied through a second jack 10, a static load test of the follow-up pipe pile while drilling is carried out, an axial force-displacement curve is obtained, and therefore the grouting effect is evaluated.
The embodiment can be used for simulating the influence of different grouting processes and parameters such as underground water flow speed, earth covering pressure, the number and the diameter of the positions of the grout outlets, shrinkage phenomenon, static pressure grouting, pulsating grouting and the like on the grouting effect, can simulate the stratum environment more truly and improves the practicability of the invention; the grouting pressure is controlled by arranging the grout stop plate 12 and the like, so that high-pressure grouting and constant-pressure grouting are realized, and powerful support is provided for optimizing grouting materials and grouting processes of the follow-up tubular pile while drilling; the method is not only suitable for grouting simulation of the natural soil body 26, but also can be used for other manual filling projects, and solves the problem that the related grouting process of the tubular pile while drilling cannot be simulated in a refined manner at present. The device has the advantages of low processing cost, convenient use, simple processing technology, simple structure, good safety performance, light weight and easy carrying.
The device of the embodiment can realize the simulation of the bottom and middle simultaneous pulsating grouting construction process, and comprises the following specific steps:
(1) manufacturing a rectangular mold box, wherein the length, the width and the height of the mold box are respectively 1m, 1m and 1.2m, a bottom plate 19 of the mold box is a steel plate with the thickness of 3cm, a sensing hole 30 with the diameter of 22cm is drilled in the center of the bottom plate 19, 4 steel plates 22 with the thickness of 3cm are arranged around the mold box, namely four side plates 22, 6 mold water outlets/mold water inlets with the diameter of 3cm are symmetrically arranged on each side plate 2222, a cobblestone layer 27 with the thickness of 3-5cm and the diameter of 1-2cm is paved along the periphery of each side plate 22, and a cross reaction frame 9 at the top of the mold box is laid aside for later use;
(2) selecting a model pile 14, selecting a polyvinyl chloride pipe (namely a polyvinyl chloride pipe for short) with the outer diameter of 18cm, the inner diameter of 16cm and the length of 0.8m as the model pile 14, drilling grouting holes with the diameter of 1.5cm at the positions of 5cm and 35cm of the pile bottom to simulate a lower grouting hole 17 and a middle grouting hole 24 for simultaneously grouting the lower part and the middle part of the model pile 14, connecting the grouting holes with a grouting pipe 6 (a silicone tube) with the same diameter, penetrating the grouting pipe 6 out of the pile core, and attaching strain gauges 28 (preferably 120-1AA strain gauge) at the positions of 0cm, 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm and 80cm away from the lower end of the model pile 14 in order to prevent grouting liquid from flowing into the pile core from the bottom of the model pile 14 and further reducing the pressure of the grouting to cause grouting failure, sealing treatment is carried out by adopting AB glue, and the treated model pile 14 is placed aside for standby; grouting holes in the model pile 14 enable cement paste to fill the surrounding soil 26 in the best combination mode of permeation, compaction, splitting and the like so as to improve side friction resistance; the slurry diffusion traces 16 are indicated by arrows.
(3) Filling soil, namely placing a circular lower pressure sensor 21 in a circular hole in a bottom plate 19 of a model box and padding the circular lower pressure sensor in a circular foam pad 20, then filling soil, after the soil filling thickness reaches 10cm, symmetrically arranging two lower soil pressure boxes 18 at positions 25cm and 30cm away from the side edge of the model box, then placing a pore-forming barrel 31 with the outer diameter of 20cm right above the circular lower pressure sensor 21, continuously filling soil, and after the soil filling thickness reaches 80cm (at the moment, the soil layer is 70cm away from the pile bottom), symmetrically arranging two upper soil pressure boxes 11 at positions 25cm and 30cm away from the side edge of the model box in the same way;
(4) the hole forming barrel 31 is pulled out, a simulated drilled hole with the diameter of 20cm is formed in the soil body 26 at the moment, the diameter of the simulated drilled hole is larger than the diameter (18cm) of the model pile 14, then the model pile 14 is placed into the round hole, the distance between the model pile 14 and the surrounding soil body 26 is calculated to be 1cm, and the distance between the soil body 26 and the top end of the model pile 14 is 10cm at the moment;
(5) placing a grout stopping plate 12, wherein the grout stopping plate 12 consists of two steel plates with the length, width and height of 40cm, 20cm and 2cm respectively, a long screw 32, a screw hole 33 and a semicircular hole 34, each steel plate is provided with a semicircular hole 34 with the diameter of 18.2cm on one side with the side length of 40cm, the semicircular hole is slightly larger than the diameter (18cm) of the model pile 14, the grout stopping plate 12 is connected with the model pile 14 and is sealed through a sealing ring, fine pinhole-shaped micropores are arranged on the sealing ring so as to discharge air during grouting, cement paste is subjected to pressure building to simulate different grouting pressure effects, and soil is continuously filled to the pile top of the model pile 14;
(6) applying confining pressure, controlling the pressure applied to the soil 26 by the first jack 7 through the reading of the soil pressure cell, and simulating the formation pressure (about 0.8MPa) of the formation with the depth of 60 meters;
(7) simulating underground water, connecting the water inlet 29 of the tank with a water source, and starting the next step after the water flow speed of the water outlet 13 of the tank is stable;
(8) connecting grouting pipes 6, respectively connecting 2 grouting pipes 6 with two grouting machines 1, namely sequentially connecting the grouting pipes 6 with a control valve 5, a pressure gauge 4, a pressure regulating valve 3, a slurry storage tank 2 and a multifunctional cement grouting machine 1, and connecting the other grouting pipe 6 in the same way;
(9) carrying out a grouting test, starting the multifunctional cement grouting machine 1, opening the pressure regulating valve 3, opening the control valve 5 for grouting when the pressure of the pressure gauge 4 reaches 1MPa, opening and closing the control valve 5 every 20s in order to simulate a pulsating grouting process, finishing grouting after the pressure of the grouting pressure gauge 4 is not reduced any more, and preparing the residual grout in the grout storage tank 2 into a 70 concrete test block for later use;
(10) curing the grouting body 25, after grouting, naturally curing the grouting body 25 and the concrete test block of 70 x 70 for 28 days, then carrying out a strength test on the concrete test block, carrying out a next test after the strength test reaches a specified strength, and otherwise, continuing curing;
(11) the static load test of following the tubular pile while drilling, treat that grout 25 reaches certain intensity after, carry out the static load test research of following the tubular pile while drilling, exert axial load through axial second jack 10, gather the load of 14 upper portions of model pile and lower part through upper portion pressure sensor 8 and lower part pressure sensor 21, gather pile body through pile body foil gage 28 and meet an emergency, obtain the load displacement curve (Q-S curve) of the static load test of following the tubular pile while drilling, through calculating bearing capacity and the side frictional resistance of obtaining following the tubular pile while drilling, thereby judge the slip casting effect.
The invention can realize a multifunctional grouting model box, provides a specific grouting method, and can realize the simulation of real stratum environment by changing the type of soil layer soil body 26, so that the optimization of the pile side grouting process of the pipe-following pile while drilling becomes possible, the grouting cost is saved, the grouting quality is improved, and the field grouting is guided by an indoor test, thereby promoting the popularization of the large-diameter drilling-following pile. The method has the advantages of clear steps, simplicity, practicability, low cost and high efficiency.
The present invention is not limited to the above-described embodiments, and various changes and modifications of the present invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.
Claims (10)
1. An experimental device for simulating pile side grouting of a pipe-following pile while drilling is characterized by comprising a model box system, a loading system, a water supply system and a grouting system;
the model box system comprises a model box, a grout stopping plate and a model pile with a sealed bottom end; a plurality of tank water inlets and tank water outlets are formed in the side wall of the model tank, and the water outlet of the water supply system is communicated with the tank water inlets; soil is filled in the model box, a simulated drilling hole is formed in the soil, and the diameter of the simulated drilling hole is larger than that of the model pile; the model pile is coaxially arranged in the simulated drilling hole, a plurality of grouting holes for grouting the gap are formed in the model pile, and a grouting outlet of the grouting system is communicated with the grouting holes; the grout stopping plate is provided with a through hole matched with the model pile, and the grout stopping plate is sleeved at the upper end of the model pile through the through hole so as to seal a gap between the model pile and the soil body;
the loading system comprises a confining pressure dividing device for applying pressure to the soil body, an axial pressure dividing device for applying pressure to the model pile and a plurality of strain gauges; the confining pressure separating device is arranged at the top end of the model box and located on two sides of the model pile, the axial pressure separating device is arranged at the top end of the model pile, and the strain gauge is attached to the outer side wall of the model pile.
2. The experimental facility as claimed in claim 1, wherein the grouting system comprises a slurry storage tank, a slurry injector for injecting slurry in the slurry storage tank into the gap; the grouting device is characterized by further comprising a control valve, wherein the control valve is arranged on the grouting pipe communicated with the grouting hole and the outlet of the grout storage pool.
3. The experimental device of claim 2, wherein the grouting system further comprises a pressure regulating valve and a pressure gauge, the pressure regulating valve is arranged on the grouting pipe between the slurry storage tank and the control valve, and the pressure gauge is arranged on the grouting pipe between the pressure regulating valve and the control valve.
4. The experimental facility according to claim 1, wherein the loading system further comprises a first pressure detector for detecting a pressure value in the soil body and a second pressure detector for detecting a pressure value loaded on the model pile, the first pressure detector is disposed at the upper end and the lower end of the soil body and faces the confining pressure sub-facility, and the second pressure detector is disposed at the top end and the bottom end of the model pile and faces the axial pressure sub-facility.
5. The experimental apparatus as claimed in claim 4, wherein the bottom plate of the mold box is provided with a sensing hole, the bottom plate of the mold box is provided with a sensing pad, and the second pressure detector is arranged on the sensing pad and located in the sensing hole.
6. The experimental apparatus as claimed in claim 1, wherein the loading system further comprises a reaction frame, the confining pressure sub-device comprises a first jack, the axial pressure sub-device comprises a second jack, the reaction frame is disposed at a top end of the model box, two ends of the first jack are respectively abutted against the reaction frame and the model box, and two ends of the second jack are respectively abutted against the reaction frame and the model box.
7. The experimental device as claimed in claim 1, wherein the model pile comprises a plurality of model piles, and the number of the grouting holes on each model pile is different, or the hole diameter is different, or the distance from the top end of the model pile is different.
8. The experimental facility as claimed in claim 1, further comprising a hole forming bucket disposed in the mold box when the mold box is filled with soil to form the simulated borehole in the soil body when the hole forming bucket is extracted, the hole forming bucket comprising a plurality of holes each having a different diameter.
9. The experimental device of claim 1, wherein the grout stopping plate comprises a first sub-plate and a second sub-plate, the first sub-plate is provided with a first semicircular arc, first threaded holes are formed in the first sub-plate and located on two sides of the first semicircular arc, second semicircular arcs and second threaded holes are formed in the second sub-plate and correspond to the first semicircular arc and the first threaded holes respectively, and the first sub-plate and the second sub-plate are fixed on the model pile through bolts.
10. The experimental facility as claimed in claim 1, wherein a permeable rock layer is uniformly laid between the side wall of the model box and the soil body.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911393033.6A CN111173049A (en) | 2019-12-30 | 2019-12-30 | Experimental device for be used for simulating following with boring pipe stake pile side slip casting |
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| CN201911393033.6A CN111173049A (en) | 2019-12-30 | 2019-12-30 | Experimental device for be used for simulating following with boring pipe stake pile side slip casting |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116735378A (en) * | 2023-05-29 | 2023-09-12 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116735378A (en) * | 2023-05-29 | 2023-09-12 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
| CN116735378B (en) * | 2023-05-29 | 2024-04-16 | 广州建筑股份有限公司 | Device and method for testing along-drilling follow pipe pile side grouting shear model |
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