CN108442421B - Large-diameter tubular pile centrifugal test model manufacturing equipment and working method thereof - Google Patents
Large-diameter tubular pile centrifugal test model manufacturing equipment and working method thereof Download PDFInfo
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- CN108442421B CN108442421B CN201810364784.4A CN201810364784A CN108442421B CN 108442421 B CN108442421 B CN 108442421B CN 201810364784 A CN201810364784 A CN 201810364784A CN 108442421 B CN108442421 B CN 108442421B
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Abstract
The equipment for manufacturing the large-diameter tubular pile centrifugal test model comprises a device for cutting and scraping a model soil sample in a model box, a hole guiding and soil taking device and a pile pressing and backfilling device, and is characterized in that: the hole guiding and soil taking device adopts the following structure: the thin-wall lead hole soil sampling pipe is guided to limit the position by a lead hole limiting ring and a lead hole; the upper end of the thin-wall hole leading soil sampling pipe is connected with a vacuum pump through an adapter and a vacuum suction nozzle; the hole guiding and soil taking device is also provided with a ventilation thin tube which can be inserted into the thin-wall hole guiding and soil taking tube, the position of the ventilation thin tube is limited by a thin tube limiting ring, and an arc-shaped cutting piece is vertically fixed at the lower end of the ventilation thin tube; the upper end of the ventilation tubule is connected with a vacuum pump through a vacuum suction nozzle. The method can finish the operations of soil sample leveling, hole guiding soil taking, pile inserting and backfilling under the condition of minimal disturbance of foundation soil in a normal gravity field, and finish the similar simulation of pile-soil contact after high gravity field pre-consolidation, and is particularly suitable for the centrifugal test of the large-diameter pipe pile of the saturated soft clay foundation.
Description
Technical Field
The invention relates to the field of geotechnical centrifugal model tests, in particular to a large-diameter tubular pile centrifugal test model manufacturing device. The invention also relates to a method for operating such a modelling apparatus.
Background
The geotechnical centrifugal model test creates a stress field with the same stress level as the prototype for the model by means of high-speed rotation of the centrifuge, so that the characters of the prototype are reproduced in the model, and the model within one meter of height can be used for simulating the prototype working conditions of dozens of meters or even hundreds of meters under the high-gravity field. The geotechnical centrifugal model test technology is used as the most effective physical model test method, almost relates to all fields of civil engineering, and becomes one of the most advanced and most main research means in geotechnical engineering technical research taking self weight as a main load.
The prototype reappearance of the geotechnical centrifugal model test is embodied on the basis that the geotechnical centrifugal model test and the geotechnical centrifugal model test meet the similar principle. Similar methods such as geometry, materials, static power and the like in the model design process are all circulated, and how to reasonably prepare the scaled model to fully reflect the actual construction working conditions on site is difficult to realize and difficult to standardize and unify. Relevant documents such as 'geotechnical centrifugal model test technical specification' DL/T5102-2013 and the like all provide model design and manufacturing principles, but specific solutions are few aiming at specific problems.
The large-diameter tubular pile represented by the PCC pile is characterized in that foundation soil is arranged inside and outside the pile, so that internal and external frictional resistance can be provided simultaneously, and the large-diameter tubular pile can be used as a single-pile foundation, a grouped pile foundation and a composite foundation. When a centrifugal model is manufactured, an aluminum alloy pipe is usually used for replacing a large-diameter pipe pile according to the compression strength equivalent or bending strength equivalent, so that the model pile is usually a long and thin pipe, and the pile spacing is small after the pile group foundation is reduced in size; in addition, the side wall of the large-diameter tubular pile is rougher than metal such as aluminum alloy, and the surface of the model pile is roughened in a geotechnical centrifugal test so that the pile-soil contact is similar. In principle, the pile forming process should be carried out in a high gravity field environment in which a centrifugal machine operates, but the high gravity field pile forming cost of a group pile centrifugal test model for realizing the large-diameter pipe piles is very high, and reports are not found at present; the pile forming operation of the existing large-diameter tubular pile centrifugal model is manually completed under the condition of 1 g gravity.
However, geometric fabrication errors and the way in which the centrifugal model operates in the normal gravity field are magnified by several orders of magnitude in the high gravity field. The difficulty of the large-diameter tubular pile centrifugal test model mainly comprises how to consider the similar simulation in the aspects of pile hole manufacturing, pile internal filling, pile soil contact and the like. The foundation model can be completely damaged by directly inserting the pile group model with the roughened surface into a model soil sample under a normal gravity field, pile arrangement is completed by applying a hole leading type pile inserting mode, foundation disturbance in the pile inserting process under the normal gravity field condition is reduced to the maximum extent, and pile filling and effective simulation of pile soil contact are the keys for manufacturing the large-diameter tubular pile centrifugal test model.
The Nanjing institute of Water conservancy science has advanced geotechnical centrifugal test equipment, and a great deal of research is carried out on the manufacture of centrifugal test models. Aiming at the problems, the invention provides equipment for manufacturing a large-diameter tubular pile centrifugal test model and a working method thereof.
Disclosure of Invention
In order to solve the technical problem of similar simulation in the manufacturing process of the large-diameter tubular pile geotechnical centrifugal test model, the invention provides equipment for manufacturing the large-diameter tubular pile centrifugal test model, and the invention also provides a working method of the equipment for manufacturing the large-diameter tubular pile centrifugal test model. The invention can avoid the overlarge disturbance of the hand-press type lead hole to the model soil sample, reduce the bottom vacuum resistance when the thin-wall lead hole soil sampling pipe is pulled out of the pile position, and avoid the shrinkage of the pile position and the insufficient sampling of the lead hole. The invention avoids using remolded soil as the filling soil in the pile, can unify and standardize the model making process and eliminate the elevation error of the model making. The size of the hole guiding soil taking device and the size of the soil beating and backfilling device are matched, the operation modes are correlated, the hole guiding soil taking, pile inserting and backfilling operations can be completed under the condition of minimal disturbance of foundation soil in a normal gravity field, the pile-soil contact similarity is completed after the pre-consolidation, and the hole guiding soil taking device and the soil beating and backfilling device are particularly suitable for manufacturing large-diameter pipe pile centrifugal test models on saturated soft clay foundations.
In order to achieve the purpose, the invention adopts the following technical scheme:
the utility model provides a major diameter tubular pile centrifugal test model preparation equipment, includes the device of cutting strickle model soil sample in the model case, draws hole device of fetching earth and presses a backfill device, its characterized in that: the hole guiding and soil taking device adopts the following structure: the device is provided with a thin-wall lead hole soil sampling pipe, and the thin-wall lead hole soil sampling pipe is limited in position by a lead hole limiting ring and a lead hole guide; the upper end of the thin-wall hole leading soil sampling pipe is connected with a vacuum pump through an adapter and a vacuum suction nozzle; the hole leading and soil taking device is also provided with a ventilation thin tube which can be inserted into the thin-wall hole leading and soil taking tube, the position of the ventilation thin tube is limited by a thin tube limiting ring, and the lower end of the ventilation thin tube is vertically fixed with an arc-shaped cutting piece; the upper end of the ventilation tubule is connected with a vacuum pump through a vacuum suction nozzle.
In other words, the top end of the thin-wall hole leading soil sampling pipe can automatically sink in the model soil sample after being connected with the vacuum pump, so that the phenomenon that the model soil sample is disturbed too much by hand-pressing hole leading is avoided; after the thin-wall hole leading soil sampling pipe sinks to the right position, the ventilating thin pipe with the arc-shaped chips at the bottom end is sunk to the tail end of the soil sampling pipe by using a vacuum pump in a manner of clinging to the inner wall of the thin-wall hole leading soil sampling pipe, and the ventilating thin pipe is rotated to cut off a soil sample at the bottom end of the hole leading soil sampling pipe so as to be separated from bottom soil; after the ventilation thin tube is taken out, air vents are formed inside the thin-wall leading hole soil sampling tube, the thin-wall leading hole soil sampling tube is pulled out to complete pile position hole forming, and then a pile pressing device is used for pressing the model pile into the hole position; connecting the soil-working pipe with a vacuum pump, taking out the soil in the thin-wall lead hole soil-working pipe, and filling the soil-working pipe into the model pile by using a soil-working rod; the hole guiding soil taking device and the soil beating and backfilling device are matched in size, operation modes are correlated, and hole guiding soil taking, pile inserting and backfilling operations can be completed under the condition of minimal disturbance of foundation soil.
The device for cutting and scraping the model soil sample comprises: the scraping cross beam is fixedly provided with a scraping footage through a pin, and the working end of the scraping footage is provided with a soil cutting steel wire.
The pile pressing backfill device comprises: pile pressing beam, fixed-length pile pressing rod, soil-digging pipe, soil-shifting rod, hole-guiding guide and vacuum pump.
The invention has the following optimization scheme:
the substitute material, the outer diameter, the wall thickness and the length of the model pile are determined according to the similar principle and the experimental design acceleration, the inner side and the outer side of the pile body are subjected to rough treatment, and the pile-soil friction coefficient is the same as the field working condition.
The model soil sample is saturated soft clay, and can be prepared in a model box by adopting a centrifugal force field consolidation method and a consolidation instrument prepressing method.
The structure of the strickling beam is that the strickling beam is longer than the width of the model box, a pair of strickling footage orthogonal to the strickling beam is respectively fixed in the grooves at two sides after being connected by a pin, the length of the strickling footage is 30-60 cm, and the working depth of the strickling beam is adjustable; the cross section of each of the leveling footage is rectangular, the side length is 1-3 cm, and the width of the outer edge of each of the two leveling footages is 2-4 mm smaller than the width of the model box; the bottom end of the strickling footage is connected with the soil cutting steel wire, and the diameter of the soil cutting steel wire is 0.4-0.8 mm; and the strickling beam is arranged on the model box to transversely translate, and the model soil sample can be cut and strickled to a designed depth through the soil cutting steel wire.
The thin-wall hole leading soil sampling pipe is made of stainless steel, the outer diameter of the thin-wall hole leading soil sampling pipe is the same as that of the model pile, the wall thickness is 0.2-0.5 mm, and the thin-wall hole leading soil sampling pipe is 8-15 cm longer than the depth of a hole leading; the soil inlet end of the thin-wall guide hole soil sampling pipe is provided with a cutting edge, and the top end of the thin-wall guide hole soil sampling pipe automatically sinks to guide a hole for sampling through vacuum suction after being connected with the vacuum pump through an adapter; before the thin-wall hole leading soil sampling pipe is used, lubricating oil is smeared on the inner wall and the outer wall of the thin-wall hole leading soil sampling pipe so as to reduce disturbance to the model soil sample during hole leading; leading the thin-wall lead hole soil sampling pipe to vertically sink by using lead hole guiding, and controlling the depth of the lead hole by using a lead hole limiting ring; the depth of the lead hole is 5-8 cm.
The ventilation thin tube is a stainless steel hollow thin tube, is 4-6 cm longer than the thin-wall lead hole soil sampling tube, has the wall thickness of 0.2-0.3 mm, and has the outer diameter of 1-3 mm and not more than the wall thickness of the model pile; the lower end of the ventilation thin tube is welded with the arc-shaped chips, the arc-shaped chips are made of high-modulus stainless steel with the thickness of 0.4-0.8 mm and the height of 3-5 mm, the arc length radius of the arc-shaped chips is equal to the inner diameter of the thin-wall lead hole soil sampling tube, and the arc length radius of the arc-shaped chips is 1/4-2/5 of the circumference; the arc-shaped chips and the bottom end of the ventilation tubule are attached to the inner wall of the thin-wall hole leading soil taking pipe which is sunk in place, the vacuum pump is used for connecting the top of the ventilation tubule, and the bottom end of the ventilation tubule is sunk to the bottom end of the thin-wall hole leading soil taking pipe through vacuumizing; rotating the upper part of the ventilation tubule, cutting the bottom soil by the arc-shaped chips, separating most of the bottom soil in the thin-wall lead hole soil sampling tube from a model soil sample, resetting the arc-shaped chips and pulling out the ventilation tubule, forming air vents in the soil sample in the thin-wall lead hole soil sampling tube, balancing the air pressure in the hole site formed when the thin-wall lead hole soil sampling tube is pulled out, and reducing the disturbance of lead hole soil sampling.
The model pile is pressed into a pile hole through the pile pressing device; the pile pressing device comprises a pile pressing cross beam and a fixed-length pile pressing rod; the pile pressing cross beam is provided with an upper through groove and a lower through groove which are longer than the width of the model box, so that the fixed-length pile pressing rod main body can penetrate through the through groove; the upper end of the fixed-length pile pressing rod is provided with a circular truncated cone expansion head, and the fixed-length pile pressing rod is matched with the pile pressing beam to press all model piles to a design plane.
The soil-working pipe is made of stainless steel, the wall thickness is 0.2-0.5 mm, the outer diameter is 0.5 mm smaller than the inner diameter of the thin-wall lead hole soil-taking pipe and 0.5 mm smaller than the inner diameter of the model pile, and the length of the soil-working pipe just penetrates through the thin-wall lead hole soil-taking pipe; after the adapter is connected with the vacuum pump, a soil sample in the thin-wall hole leading soil sampling pipe can be taken out; and as the model pile is thicker than the thin-wall hole leading soil taking pipe, the original soil sample outside the range of the vent hole in the thin-wall hole leading soil taking pipe is taken away by the soil beating pipe and is used for backfilling into the model pile.
The soil pushing rod is made of plastic, is 20 cm longer than the soil pushing pipe, has an outer diameter smaller than the inner diameter of the soil pushing pipe by 1 mm, and is used for pushing soil in the soil pushing pipe into the model pile.
The technical scheme for completing the second invention task of the application is that the working method of the large-diameter tubular pile centrifugal test model manufacturing equipment is characterized by comprising the following steps of:
(1) manufacturing a saturated clay model soil sample in a model box, and manufacturing a model pile with a roughened surface according to the field pile soil friction coefficient and similar requirements;
(2) adjusting the working depth and width of the strike-off feed on the strike-off beam according to the design depth of the surface of the model soil sample and the net width of the model box, clamping and fixing by using pins, and tightening the soil cutting steel wire at the working end of the strike-off feed; digging advancing grooves for leveling the inlet ruler at two sides of the model soil sample, placing a device for cutting and leveling the model soil sample in a model box, uniformly and slowly moving the device for cutting and leveling the model soil sample along the long edge, and cutting a surface with a designed depth in the model soil sample;
(3) guiding and fixing the guide hole at the pile position, adjusting the position of the guide hole limiting ring on the thin-wall guide hole soil sampling pipe according to the depth of the guide hole, smearing lubricating oil on the inner wall and the outer wall of the thin-wall guide hole soil sampling pipe, and connecting the top end of the thin-wall guide hole soil sampling pipe with a vacuum pump through an adapter; vertically inserting the cutting edge of the thin-wall hole leading soil sampling pipe into a model soil sample through hole leading guide, starting a vacuum pump, sucking air in the thin-wall hole leading soil sampling pipe, and slowly and vertically sinking the thin-wall hole leading soil sampling pipe under vacuum suction until a hole leading limiting ring is in guide contact with a hole leading;
(4) adjusting the position of the thin tube limiting ring relative to the ventilation thin tube to enable the distance between the thin tube limiting ring and the bottom end of the arc-shaped chipping piece to be equal to the length of the thin-wall hole leading soil sampling tube; coating lubricating oil on the ventilation tubule, connecting the top end of the ventilation tubule with a vacuum pump through a vacuum suction nozzle, enabling the arc-shaped chippings and the bottom of the ventilation tubule to be tightly attached to the inner wall of the thin-wall hole leading soil sampling pipe to be vertically inserted into the surface of a model soil sample, and starting the vacuum pump to enable the ventilation tubule to slowly and vertically sink to a tubule limiting ring to be contacted with the top end of the thin-wall hole leading soil sampling pipe;
(5) rotating the top of the ventilation tubule to the limit in the forward direction to cut the bottom soil of the thin-wall hole leading soil sampling tube by the arc-shaped chippings at the bottom of the ventilation tubule, and rotating the ventilation tubule in the reverse direction to reset the arc-shaped chippings and then cling to the inner wall of the thin-wall hole leading soil sampling tube;
(6) uniformly and slowly vertically pulling out the ventilation thin tube, and forming a ventilation hole at the inner wall of the thin-wall hole leading soil sampling tube; uniformly and slowly vertically pulling out the thin-wall hole leading soil sampling pipe to form a pile hole at the pile position of the model soil sample;
(7) using a guide hole guiding and pile pressing device, vertically inserting a model pile into a pile hole, and accurately pressing the pile top to a design plane;
(8) positively inserting the top end of the soil-working pipe into soil in the thin-wall hole leading and soil-taking pipe, connecting the top of the soil-working pipe with a vacuum pump through an adapter, enabling the soil-working pipe to slowly penetrate through the thin-wall hole leading and soil-taking pipe by utilizing vacuum suction, and transferring undisturbed soil in the thin-wall hole leading and soil-taking pipe into the soil-working pipe;
(9) positively inserting the soil-driving pipe into the model pile until the soil-driving pipe reaches the bottom, inserting the soil-driving rod into the soil-driving pipe, uniformly and slowly vertically pulling out the soil-driving pipe, and driving the soil in the pipe into the model pile;
(10) cleaning each device, and repeating the steps (1) to (9) to complete the layout of the next model pile;
(11) after all model piles are arranged, placing the model in a set supergravity field for pre-consolidation to finish the similar simulation of pile-soil contact, wherein the running time of a centrifuge is similar to the corresponding time of site construction.
Compared with the prior art, the invention has the advantages and beneficial effects that:
the thin-wall lead hole soil sampling pipe is connected with the vacuum pump and then automatically sinks in the model soil sample by using vacuum suction, so that overlarge disturbance of the hand-press lead hole to the model soil sample can be avoided. The ventilation thin tube with the arc-shaped cutting piece at the bottom end is used for cutting the inside of the thin-wall hole leading soil sampling tube and forming a ventilation hole, so that the bottom vacuum resistance of the thin-wall hole leading soil sampling tube when the pile position is pulled out can be reduced, and the phenomena of pile position shrinkage and insufficient hole leading sampling are avoided. The soil sample in the soil sampling pipe is taken out by the soil sampling pipe through the thin-wall leading hole by using a vacuum suction method and then is driven into the model pile, so that the remolded soil is prevented from being used as the filling soil in the pile. The cutting and strickling device is used for cutting the model soil sample to the design depth, and the guide hole guiding and pile pressing device is used for pressing all model piles to the design plane, so that the model manufacturing process can be unified and standardized, and the elevation error of the model can be eliminated. The size of the hole guiding soil taking device and the size of the soil beating and backfilling device are matched, the operation modes are correlated, the hole guiding soil taking, pile inserting and backfilling operations can be completed under the condition of minimal disturbance of foundation soil in a normal gravity field, the pile-soil contact similarity is completed after the pre-consolidation, and the hole guiding soil taking device and the soil beating and backfilling device are particularly suitable for manufacturing large-diameter pipe pile centrifugal test models on saturated soft clay foundations.
Drawings
FIG. 1 is a hole guiding and soil sampling device manufactured by a large-diameter tubular pile centrifugal test model;
3 FIG. 3 2 3 is 3 a 3 cross 3- 3 sectional 3 view 3 A 3- 3 A 3 of 3 FIG. 3 1 3; 3
FIG. 3 is a hole guiding and ventilating device manufactured by a large-diameter tubular pile centrifugal test model;
FIGS. 4-1 and 4-2 are the device for cutting and scraping the model soil sample of the large-diameter tubular pile centrifugal test model according to the invention;
FIG. 5 is a method for feeding soil into a thin-wall hole-guiding soil-sampling pipe manufactured by a large-diameter tubular pile centrifugal test model according to the invention;
FIG. 6 is a method for making a large-diameter tubular pile centrifugal test model by using a ventilating thin tube to feed soil;
FIG. 7 is a method for cutting the bottom soil of a thin-wall soil sampling pipe with a thin-wall guide hole by using a ventilation tubule manufactured by a large-diameter tubular pile centrifugal test model;
FIG. 8 is a cross-sectional illustration of the cutting operation of FIG. 7;
FIG. 9 is a drawing of a taking out ventilation tubule for manufacturing a large-diameter tubular pile centrifugal test model according to the invention;
FIG. 10 is a drawing of a thin-wall hole-leading soil-sampling pipe made by the centrifugal test model of the large-diameter tubular pile of the present invention;
FIGS. 11-1 and 11-2 are views of pile pressing devices and operations for manufacturing a centrifugal test model of a large-diameter tubular pile according to the invention;
FIG. 12 shows a soil-working pipe and a soil sampling method thereof manufactured by the centrifugal test model of the large-diameter tubular pile according to the invention;
FIG. 13 shows a method for driving earth in a model pile manufactured by a large-diameter tubular pile centrifugal test model according to the present invention;
fig. 14-1 and 14-2 are side views and plan views, respectively, of an embodiment to which the present invention is applied.
Wherein, fig. 5-14-1 and 14-2 are diagrams of the working method of the large-diameter tubular pile centrifugal test model manufacturing equipment.
In the figure: 1. the device comprises a thin-wall hole guiding soil sampling pipe, 2, a hole guiding limiting ring, 3, a hole guiding guide, 4, a vacuum pump, 5, a vacuum suction nozzle, 6, an adapter, 7, a ventilation thin pipe, 8, an arc-shaped chipping piece, 9, a thin pipe limiting ring, 10, a model pile, 11, a model soil sample, 12, a soil beating pipe, 13, a soil pushing rod, 14, a scraping beam, 15, a scraping advancing ruler, 16, a soil cutting steel wire, 17, a pin, 18, a pile pressing beam, 19, a fixed-length pile pressing rod, 20, a model box, 21, an air vent, 22 and a embankment model.
Detailed Description
Embodiment 1, a large-diameter tubular pile centrifugal test model manufacturing device and a working method thereof, as shown in fig. 1 to 14-1 and 14-2, the large-diameter tubular pile centrifugal test model manufacturing device of the present invention mainly comprises a cutting and leveling device, a hole guiding and soil sampling device, a pile pressing and backfilling device, a leveling footage 15 with a soil cutting steel wire 16 at the bottom end is used, a leveling cross beam 14 is uniformly moved on a model box 20, and a model soil sample 11 is cut to a designed depth; the thin-wall hole leading soil sampling pipe 1 can automatically sink under the action of vacuum suction after being connected with the vacuum pump 4, the ventilation tubule 7 with the arc-shaped cutting blade 8 at the bottom end is tightly attached to the inner wall of the thin-wall hole leading soil sampling pipe 1 and inserted into soil by using a suction sinking method, the bottom soil is cut off in a rotary mode, the ventilation tubule 7 is pulled out to form a ventilation hole 21, and hole shrinkage and insufficient soil sampling caused by bottom vacuum resistance when the thin-wall hole leading soil sampling pipe 1 is pulled out are avoided; similarly, a vacuum pump 4 is used for assisting the soil-working pipe 12 to take out an undisturbed soil sample in the thin-wall hole-leading soil-working pipe 1, and a soil-shifting rod 13 is used for filling the undisturbed soil sample into the model pile 10; each model pile is pressed to a design plane by using a guide hole guide and pile pressing cross beam 18 and a fixed-length pile pressing rod 19 before filling. The vacuum suction assists in guiding the hole to take out soil, assists in ventilating when forming the hole, and simultaneously backfills the original-state soil taken out into the model pile 10, so that disturbance of the whole molding process to the model soil sample 11 is greatly reduced, a scraping device is used for cutting a soil sample plane and a pile pressing device is used for pressing all model piles to a design plane, the molding elevation error is eliminated, and the method is suitable for preparing various centrifugal test models based on large-diameter pipe piles on a saturated soft clay foundation. The specific implementation mode is as follows:
1) manufacturing a saturated clay model soil sample in a model box 20, and manufacturing a model pile 10 with a roughened surface according to the field pile-soil friction coefficient and similar requirements;
2) adjusting the working depth and width of the leveling footage 15 on the leveling beam 14 according to the surface design depth of the model soil sample 11 and the net width of the model box 20, clamping and fixing by using a pin 17, and tightening a soil cutting steel wire 16 at the working end of the leveling footage 15; digging out advancing grooves of the leveling advancing ruler 15 on two sides of the model soil sample 11, placing a leveling device in the model box 20, then uniformly and slowly moving along the long edge, and cutting out a surface with a designed depth in the model soil sample 11;
3) fixing a guide hole guide 3 at a pile position, adjusting the position of a guide hole limiting ring 2 on a thin-wall guide hole soil sampling pipe 1 according to the depth of the guide hole, smearing lubricating oil on the inner wall and the outer wall of the thin-wall guide hole soil sampling pipe 1, and connecting the top end of the thin-wall guide hole soil sampling pipe with a vacuum pump 4 through an adapter 6; vertically inserting the cutting edge of the thin-wall hole leading soil sampling pipe 1 into a model soil sample 11 through hole leading guide, starting a vacuum pump 4, sucking air inside the thin-wall hole leading soil sampling pipe 1 away, and slowly and vertically sinking the thin-wall hole leading soil sampling pipe under vacuum suction until a hole leading limiting ring 2 is contacted with a hole leading guide 3;
4) adjusting the position of the thin tube limiting ring 9 relative to the ventilation thin tube 7 to enable the distance between the thin tube limiting ring and the bottom end of the arc-shaped chipper 8 to be equal to the length of the thin-wall hole leading soil sampling tube 1; coating lubricating oil on the ventilation tubule 7, connecting the top end of the ventilation tubule 7 with a vacuum pump 4 through a vacuum suction nozzle 5, enabling the bottom of the arc-shaped chipper 8 and the bottom of the ventilation tubule 7 to be tightly attached to the inner wall of the thin-wall hole leading soil sampling pipe 1 and vertically inserted into the surface of a model soil sample 11, and starting the vacuum pump 4 to enable the ventilation tubule 7 to slowly and vertically sink until a tubule limiting ring 9 is contacted with the top end of the thin-wall hole leading soil sampling pipe 1;
5) the top of the ventilation tubule 7 is rotated to the limit in the forward direction, so that the arc-shaped chips 8 at the bottom of the ventilation tubule cut the bottom soil of the thin-wall hole leading soil sampling pipe 1, and the ventilation tubule 7 is rotated in the reverse direction, so that the arc-shaped chips 8 are restored and then cling to the inner wall of the thin-wall hole leading soil sampling pipe 1;
6) uniformly and slowly vertically pulling out the ventilation tubules 7, and forming a ventilation hole 21 on the inner wall of the thin-wall hole leading soil sampling pipe 1; uniformly and slowly vertically pulling out the thin-wall hole leading soil sampling pipe 1 to form a pile hole at the pile position of the model soil sample 11;
7) using a guide hole guide 3 and a pile pressing device, vertically inserting a model pile 10 into a pile hole, and accurately pressing the pile top to a design plane;
8) the top end of the soil-working pipe 12 is inserted into soil in the thin-wall hole-leading soil-taking pipe 1 in the forward direction, the top of the soil-working pipe 12 is connected with a vacuum pump 4 through an adapter 6, the soil-working pipe 12 slowly penetrates through the thin-wall hole-leading soil-taking pipe 1 by utilizing vacuum suction, and original soil in the thin-wall hole-leading soil-taking pipe 1 is transferred into the soil-working pipe 12;
9) positively inserting the soil-working pipe 12 into the bottom of the model pile 10, inserting the soil-working rod 13 into the upper part of the soil-working pipe 12 without moving, uniformly and slowly vertically pulling out the soil-working pipe 12, and driving the soil in the pipe into the model pile 10;
10) cleaning each device, and repeating 1) to 9), so as to complete the layout of the next model pile;
11) after all model piles are arranged, placing the model box 20 in a set gravity field for pre-consolidation to complete the similar simulation of pile-soil contact and arranging sensors, wherein the running time of a centrifuge is similar to the corresponding time of field construction;
12) as shown in fig. 14-1 and 14-2, after the pile-soil composite foundation is molded, the next step of making the embankment model 22 may be performed.
It should be noted that, the equipment for manufacturing centrifugal test model of large-diameter tubular pile and the working method thereof according to the present invention are applicable to single-pile foundation, multi-pile foundation and pile group foundation, and the above example illustrates the preferred embodiment of the present invention by using the centrifugal test model of large-diameter tubular pile composite foundation under embankment, and it should be noted that, for those skilled in the art, a number of improvements and decorations can be made without departing from the principle of the present invention, and these improvements and decorations should also be regarded as the protection scope of the present invention.
Claims (4)
1. The utility model provides a major diameter tubular pile centrifugal test model preparation equipment, includes the device of cutting strickle model soil sample in the model case, draws hole device of fetching earth and presses a backfill device, its characterized in that: the hole guiding and soil taking device adopts the following structure: the device is provided with a thin-wall lead hole soil sampling pipe, and the thin-wall lead hole soil sampling pipe is limited in position by a lead hole limiting ring and a lead hole guide; the upper end of the thin-wall hole leading soil sampling pipe is connected with a vacuum pump through an adapter and a vacuum suction nozzle; the hole leading and soil taking device is also provided with a ventilation thin tube which can be inserted into the thin-wall hole leading and soil taking tube, the position of the ventilation thin tube is limited by a thin tube limiting ring, and the lower end of the ventilation thin tube is vertically fixed with an arc-shaped cutting piece; the upper end of the ventilation thin tube is connected with a vacuum pump through a vacuum suction nozzle;
the thin-wall hole leading soil sampling pipe is made of stainless steel, the outer diameter of the thin-wall hole leading soil sampling pipe is the same as that of the model pile, the wall thickness is 0.2-0.5 mm, and the thin-wall hole leading soil sampling pipe is 8-15 cm longer than the depth of a hole leading; the soil inlet end of the thin-wall guide hole soil sampling pipe is provided with a cutting edge, and the top end of the thin-wall guide hole soil sampling pipe automatically sinks to guide the hole for sampling through vacuum suction after being connected with the vacuum pump through an adapter; leading the thin-wall lead hole soil sampling pipe to vertically sink by using lead hole guiding, and controlling the depth of the lead hole by using a lead hole limiting ring; the depth of the lead hole is 5-8 cm;
the ventilation thin tube is a stainless steel hollow thin tube, is 4-6 cm longer than the thin-wall lead hole soil sampling tube, has the wall thickness of 0.2-0.3 mm, and has the outer diameter of 1-3 mm and is not more than the wall thickness of the model pile; the lower end of the ventilation thin tube is connected with the arc-shaped chipping piece, the arc-shaped chipping piece is high-modulus stainless steel with the thickness of 0.4-0.8 mm and the height of 3-5 mm, the arc length radius of the arc-shaped chipping piece is equal to the inner diameter of the thin-wall lead hole soil taking tube, and the arc length of the arc-shaped chipping piece is 1/4-2/5 of the circumference of the inner diameter of the thin-wall lead hole soil taking tube; connecting the top of the ventilation tubule by using the vacuum pump, vacuumizing to enable the bottom end of the ventilation tubule to sink to the bottom end of the thin-wall lead hole soil sampling pipe, rotating the ventilation tubule, resetting and then taking out, finishing cutting of bottom soil and forming a vent hole in a soil sample in the thin-wall lead hole soil sampling pipe;
the device for cutting and scraping the model soil sample comprises a scraping beam, a scraping footage is fixed on the scraping beam through a pin, and a soil cutting steel wire is arranged at the working end of the scraping footage; the structure of the strickle beam is as follows: the length of the leveling device is longer than the width of the model box, and a pair of leveling footage orthogonal to the leveling beam is respectively fixed in the grooves at two sides after being connected by a pin; the length of the strickling footage is 30-60 cm, and the working depth of the strickling footage relative to the strickling beam is adjustable; the diameter of the soil cutting steel wire is 0.4-0.8 mm.
2. The large-diameter tubular pile centrifugal test model manufacturing equipment according to claim 1, characterized in that: the pile pressing backfilling device comprises a pile pressing beam, a fixed-length pile pressing rod, a soil driving pipe and a soil pushing rod, and further comprises the hole guiding guide and the vacuum pump; the upper end of the fixed-length pile pressing rod is provided with an expanded head platform which can move left and right along the through groove of the pile pressing beam; the pipe of digging soil is stainless steel, and wall thickness 0.2~0.5 mm, the external diameter is compared the little 0.5 mm of internal diameter of thin wall lead hole geotome, and compare the internal diameter of model pile is little 0.5 mm, the pipe length of digging soil pierces through just the thin wall lead hole geotome, through the adapter is connected the vacuum pump takes out the original state soil sample in the thin wall lead hole geotome, and with the help of bulldozing the stick with its backfill go into in the model pile.
3. The large-diameter tubular pile centrifugal test model making equipment according to claim 1 or 2, characterized in that: and the pile-soil friction coefficient of the inner side and the outer side of the model pile is the same as the field working condition.
4. The working method of the large-diameter tubular pile centrifugal test model manufacturing equipment as claimed in claim 1, is characterized by comprising the following steps:
manufacturing a saturated clay model soil sample in a model box, and manufacturing a model pile with a roughened surface according to the field pile-soil friction coefficient and similar requirements;
adjusting the working depth and width of the strike-off feed on the strike-off beam according to the design depth of the surface of the model soil sample and the net width of the model box, fixing the strike-off beam by using a pin, and tightening a soil cutting steel wire at the working end of the strike-off feed; digging advancing grooves for leveling the inlet ruler at two sides of the model soil sample, placing a device for cutting and leveling the model soil sample in a model box, uniformly and slowly moving the device for cutting and leveling the model soil sample along the long edge, and cutting a surface with a designed depth in the model soil sample;
guiding and fixing a guide hole at a pile position, adjusting the position of a guide hole limiting ring on the thin-wall guide hole soil sampling pipe according to the depth of the guide hole, smearing lubricating oil on the inner wall and the outer wall of the thin-wall guide hole soil sampling pipe, and connecting the top end of the thin-wall guide hole soil sampling pipe with a vacuum pump through an adapter; vertically inserting the cutting edge of the thin-wall hole leading soil sampling pipe into a model soil sample through hole leading guide, starting a vacuum pump, sucking air in the thin-wall hole leading soil sampling pipe, and slowly and vertically sinking the thin-wall hole leading soil sampling pipe under vacuum suction until a hole leading limiting ring is in guide contact with a hole leading;
adjusting the position of the thin tube limiting ring relative to the ventilation thin tube to enable the distance between the thin tube limiting ring and the bottom end of the arc-shaped chipping piece to be equal to the length of the thin-wall hole leading soil sampling tube; coating lubricating oil on the ventilation tubule, connecting the top end of the ventilation tubule with a vacuum pump through a vacuum suction nozzle, enabling the arc-shaped chippings and the bottom of the ventilation tubule to be tightly attached to the inner wall of the thin-wall hole leading soil sampling pipe to be vertically inserted into the surface of a model soil sample, and starting the vacuum pump to enable the ventilation tubule to slowly and vertically sink to a tubule limiting ring to be contacted with the top end of the thin-wall hole leading soil sampling pipe;
the top of the ventilation tubule is rotated to the limit in the forward direction, so that the arc-shaped chips at the bottom of the ventilation tubule cut the bottom soil of the thin-wall hole leading soil sampling tube, and the ventilation tubule is rotated in the reverse direction so that the arc-shaped chips are restored and then cling to the inner wall of the thin-wall hole leading soil sampling tube;
uniformly and slowly vertically pulling out the ventilation thin tube, and forming a ventilation hole at the inner wall of the thin-wall hole leading soil sampling tube; uniformly and slowly vertically pulling out the thin-wall hole leading soil sampling pipe to form a pile hole at the pile position of the model soil sample;
using a guide hole guiding and pile pressing backfilling device, vertically inserting a model pile into a pile hole, and accurately pressing the pile top to a design plane;
the top end of the soil-working pipe is inserted into soil in the thin-wall hole-leading soil-taking pipe in a positive direction, the top of the soil-working pipe is connected with a vacuum pump through an adapter, the soil-working pipe slowly penetrates through the thin-wall hole-leading soil-taking pipe by utilizing vacuum suction, and undisturbed soil in the thin-wall hole-leading soil-taking pipe is transferred to the soil-working pipe;
the soil-moving rod is abutted against the soil above the soil-moving pipe to be fixed until the soil-moving rod reaches the bottom, the soil-moving pipe is uniformly and slowly pulled out vertically, and the soil in the pipe is driven into the model pile;
cleaning each device, and repeating the steps (1) to (9) to complete the layout of the next model pile;
after all model piles are arranged, the model is placed in a set supergravity field to be pre-consolidated so as to complete the similar simulation of pile-soil contact, and the running time of a centrifuge is similar to the corresponding time of site construction.
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