CN211113791U - Test device for judging top surface soil arch effect action range of underground structure - Google Patents

Test device for judging top surface soil arch effect action range of underground structure Download PDF

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Publication number
CN211113791U
CN211113791U CN201921193182.3U CN201921193182U CN211113791U CN 211113791 U CN211113791 U CN 211113791U CN 201921193182 U CN201921193182 U CN 201921193182U CN 211113791 U CN211113791 U CN 211113791U
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China
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pull rod
vertical load
hole
test device
steel plate
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CN201921193182.3U
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Chinese (zh)
Inventor
吴淑伟
许四法
王哲
姚王晶
翁鹤森
崔涵晟
邱杭鹰
吕润东
陈振寰
付亚君
任康
章韬
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Zhejiang University of Technology ZJUT
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Zhejiang University of Technology ZJUT
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Abstract

The utility model discloses a test device for judging the acting range of the soil arch effect of the top surface of an underground structure, which comprises a model box with a hollow interior and a vertical load-bearing body arranged in the model box; the internal space of the vertical load bearing body is uniformly divided by n-1 partition plates to form n compartments; each compartment is provided with a pull rod type piston matched with the compartment, each pull rod type piston consists of a piston and a pull rod, each pull rod sequentially penetrates through the vertical load bearing body and the model box, the lower end part of each pull rod is provided with a load device, and each load device comprises a load bearing steel plate and a hydraulic servo jack; the pull rod is in plane contact with the bearing steel plate; the bottom of each compartment is provided with a hole; the hole is externally connected with a water outlet pipe which is transparent and provided with scales, and the water outlet pipe is communicated with the vertical load body to form a U-shaped communicating vessel. The utility model discloses simple structure, low in cost, convenient operation, measuring result is accurate.

Description

Test device for judging top surface soil arch effect action range of underground structure
Technical Field
The utility model relates to a geotechnical engineering technical field especially relates to a judge test device of underground structures top surface soil arch effect scope of action.
Background
The soil arching effect is a widely existing natural phenomenon and is a spatial effect of stress transfer shown by soil due to uneven displacement of a medium; the local soil body moves, the rest part keeps the original position still, the relative motion in the soil is resisted by the shear strength of the soil body, so that the soil body is compressed and deformed, thereby generating uneven settlement, generating the effect of mutual wedging among soil particles, and generating the arch effect in a certain range of soil layers.
Chinese patent CN 109033570A discloses a method for predicting the overburden pressure of a flexible pipeline with three-dimensional soil arch effect, which calculates and analyzes the soil arch effect caused by the uneven settlement of a foundation in the overburden soil of the pipeline, and establishes a pipeline overburden pressure prediction formula by using a rigid body limit balance theory, thereby calculating the overburden pressure of the buried flexible pipeline under the uneven settlement of the foundation. This method has limitations, only with respect to flexible pipes, and is not suitable for all underground structures.
At present, the soil arch effect action range is judged by mostly adopting a soil pressure cell to measure the vertical soil pressure and the lateral soil pressure of the soil pressure cell, so that further judgment is made, but the measured soil pressure is inaccurate and the judgment precision is influenced because the soil pressure cell is deviated by the extrusion position of a soil body in the embedding process.
In order to further improve the soil arching effect theory, it is necessary to accurately measure the specific stress variation value and determine the acting range according to p ═ γ z, so that it is necessary to develop a test device for determining the acting range of the soil arching effect on the top surface of the underground structure.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects existing in the background technology, the utility model provides a test device for judging the acting range of the top surface soil arch effect of an underground structure.
The utility model provides a technical scheme of above-mentioned problem is:
a test device for judging the acting range of the soil arch effect of the top surface of an underground structure comprises a model box with a hollow interior and a vertical load-bearing body arranged in the model box;
the periphery and the bottom of the vertical load bearing body are spliced by steel plates, the splicing part is sealed, the internal space of the vertical load bearing body is uniformly divided by n-1 partition plates with equal thickness to form n compartments, n is at least 2, and the partition plates are tightly connected with the inner wall of the vertical load bearing body; each compartment is provided with a pull rod type piston which is matched with the compartment and can slide up and down along the inner wall in the compartment, the pull rod type piston consists of a piston and a pull rod, the pull rod is installed at the bottom of the piston and sequentially penetrates through the vertical load bearing body and the model box and is provided with an extension section, the lower end part of the pull rod is provided with a load device, the load device comprises a bearing steel plate and a hydraulic servo jack, and the bearing steel plate is fixedly installed on a telescopic rod of the hydraulic servo jack and moves up and down along with the telescopic rod in the vertical direction; the pull rod is in plane contact with the bearing steel plate; the hydraulic servo jack adopts a hydraulic oil cylinder to load or unload and transmits force to the pull rod type piston through a bearing steel plate to realize the up-and-down movement of the piston; the hydraulic servo jacks uniformly control loading and unloading rates through an external computer; the bottom of each compartment is provided with a hole with the same diameter; the bottom of the model box body is provided with a through hole matched with the hole corresponding to the position of the hole of the vertical load bearing body; the hole is externally connected with a water outlet pipe which is provided with scales and is transparent, the water outlet pipe is communicated with the vertical load body and forms a U-shaped communicating vessel, and the water outlet pipe is connected with the vertical load body in a sealing way.
Furthermore, the hardness of the steel plate can at least not deform under the action of the surrounding lateral soil pressure.
Furthermore, the hole department be equipped with the connecting steel pipe, the connecting steel pipe outwards be equipped with the extension section along the through-hole of mold box bottom from the hole of vertical load body bottom, the connecting steel pipe with outlet pipe detachable connection.
Still further, the connecting steel pipe and the water outlet pipe are preferably in threaded connection.
Furthermore, four foot rests are arranged at four angular points of the bottom of the model box, so that the purpose of bearing the load of the test device and reserving a certain space for the led-out transparent plastic pipe is facilitated.
Furthermore, the material of the partition plate is a rigid plate, so that the partition plate is prevented from deforming under the action of water pressure at different depths.
Further, the connecting steel pipe is welded with the hole in a sealing mode, and the purpose is to prevent water leakage.
Furthermore, the water outlet pipe is made of ABS material, the surface of the water outlet pipe is provided with a measuring range, and the scale line of 0' of the measuring range is level to the bottom of the vertical load bearing body.
Further, the contact part of the pull rod type piston and the inner wall of the compartment is wrapped by a sealing ring.
Furthermore, the pull rod is made of 45# steel, and the joint of the lower part of the pull rod and the vertical load bearing body is wrapped by a sealing gasket.
Still further, the hardness of the pull rod can not deform at least under the action of the vertical soil pressure on the upper part.
Furthermore, four pull rods are arranged in each compartment, so that uniform stress is facilitated, and the piston cannot incline in the falling process.
Furthermore, the load-bearing area of the load-bearing steel plate is not deformed at least under the load of the upper area.
Furthermore, the main parameters of the hydraulic jack are that the maximum load is 1t, the maximum stroke is 400mm, and the maximum jacking speed is 60 mm/min.
Still further, the hydraulic jack is arranged at the right center of the lower part of the bearing steel plate.
The operation method of the test device for judging the acting range of the top surface soil arch effect of the underground structure specifically comprises the following steps:
step 1, fixing a pull rod type piston on a vertical load bearing body, and reserving a certain gap for water injection;
step 2, respectively injecting water into each compartment, firstly checking whether water leaks from the bottom of the vertical load bearing body, and readjusting the sealing gasket to ensure that no leakage occurs if water leaks;
step 3, stopping water injection when the bottom of the pull rod type piston is just contacted with the water surface and the top of the pull rod type piston is just positioned at the top surface of the vertical load bearing body, simultaneously erecting a load bearing steel plate and a hydraulic servo jack, wherein four pull rods in each partition area are arranged at four corners of the load bearing steel plate to ensure uniform stress, and the hydraulic servo jack is arranged at the center of the bottom of the load bearing steel plate;
step 4, setting an initial value of the hydraulic servo jack through a computer until the hydraulic servo jack is just in contact with the bearing steel plate to bear force, and ensuring that the pull rod type piston cannot slide downwards when being positioned at the initial position;
step 5, filling soil bodies into the box body and compacting until the whole model box is filled, and recording the initial filling height H, namely the distance between the top surface of the filling and the top surface of the vertical load bearing body;
step 6, recording the initial water level of each water outlet pipe after filling soil;
step 7, simulating the excavation process of a tunnel at the lower part of the soil body, controlling the unloading rate of a hydraulic servo jack through a computer to drive a pull rod to move, so as to drive a piston to slowly move downwards, so that the local soil body moves, the rest parts keep the original positions, and the relative movement in the soil is subjected to the resistance of the shear strength of the soil body, so that the soil body is compressed and deformed, and a soil arch effect is generated;
step 8, observing the water level change of the water outlet pipe, reading the height difference h of the water level, and then obtaining the soil pressure gamma z on different compartments at the top of the vertical load bearing bodyi＝ρghiRho is the density of water, gamma is the gravity of the filled soil, wherein i is 1-n;
9, calculating the vertical soil pressure gamma z of different compartmentsiBy the formula zi＝ρghiThe thickness z of the falling soil body of different compartments is obtained by inverse calculation of the gammaiFurther, the height H of the soil arch can be obtainedi＝H-ziThe soil arches with different heights are connected into a smooth curve, namely the action range of the soil arch effect, wherein i is 1-n.
Further, in the step 7, the unloading rate is preferably 40mm/min to 60 mm/min.
Compared with the prior art, the utility model discloses beneficial effect mainly shows:
1. the utility model provides a judge test device and test method of underground structures top surface soil arch effect scope of action can be used for studying the scope of action of structures soil arch effect under the condition of filling up.
2. Utilize the device implement test method, can avoid the skew who takes place at the buried soil pressure cell in-process, influence judgement result, the test result is accurate.
3. The test device has simple structure, low cost and convenient and easy use.
Drawings
Fig. 1 is a three-dimensional view of the test device of the present invention.
Fig. 2 is a front view of the test device of the present invention.
Figure 3 is a side view of the test device of the present invention.
Fig. 4 is a top view of the test device of the present invention.
Fig. 5 is a detailed view of the structure of the pull rod type plastic piston of the present invention.
Fig. 6 is a detailed structural view of the adjustable electric pull rod of the present invention.
Fig. 7 is a detailed view of the through hole and the vertical bearing hole of the mold box of the present invention.
Detailed Description
Referring to attached drawings 1-6, the test device for judging the acting range of the soil arch effect of the top surface of an underground structure comprises a model box 1, a foot rest 2, a through hole 3, a vertical load bearing body 4, a hole 5, a partition plate 6, a water outlet pipe 7, a piston 8, a connecting steel pipe 9, a pull rod 10, a sealing gasket 11, a load device 12, a computer 13, a load bearing steel plate 121 and a hydraulic servo jack 122.
Wherein n is 4.
Comprises a model box 1 with an internal control part and a vertical load-bearing body 4;
the periphery and the bottom of the vertical load bearing body 4 are spliced by steel plates, the spliced part is subjected to sealing treatment, the internal space of the vertical load bearing body is uniformly divided into four compartments by three partition plates 6 with equal thickness, each compartment is provided with a pull rod type piston which is matched with the compartment and can slide up and down along the inner wall in the compartment, each pull rod type piston is composed of a piston 8 and four pull rods 10, each pull rod 10 is installed at the bottom of the piston 8, sequentially penetrates through the vertical load bearing body 4 and the model box 1 and is provided with an extension section, the lower end part of each pull rod is provided with a load device 12, each load device 12 comprises a bearing steel plate 121 and a hydraulic servo jack 122, and the bearing steel plate 121 is fixedly installed on a telescopic rod of the hydraulic servo jack 122 and moves up and down along with the telescopic rod in the vertical direction; the pull rod 10 is in plane contact with the bearing steel plate 121; the hydraulic servo jack 122 adopts a hydraulic oil cylinder to load or unload and transmits force to the pull rod type piston through the bearing steel plate 121 to realize the up-and-down movement of the piston 8; the hydraulic servo jacks 122 are externally connected with a computer 13 to uniformly control loading and unloading rates; the bottom of each compartment is provided with a hole 5 with the same diameter; the bottom of the model box body is provided with a through hole 2 matched with the hole 5 corresponding to the hole of the vertical load bearing body;
the hole 5 is provided with a connecting steel pipe 9, the connecting steel pipe 9 is provided with an extension section outwards from the hole 5 at the bottom of the vertical load bearing body along the through hole 2 at the bottom of the model box body, the connecting steel pipe 9 is in threaded connection with the water outlet pipe 7, the water outlet pipe 7 is communicated with the vertical load bearing body 4 through the connecting steel pipe 9 to form a U-shaped communicating vessel, and the water outlet pipe 7 is in sealed connection with the vertical load bearing body 4;
four foot rests 3 are arranged at four corner points of the bottom of the model box, so that the purpose of bearing the load of the test device and reserving a certain space for the water supply pipe is facilitated.
The operation method of the test device for judging the acting range of the top surface soil arch effect of the underground structure specifically comprises the following steps:
step 1, fixing a pull rod type piston on a vertical load bearing body 4, and reserving a certain gap for water injection;
step 2, respectively injecting water into each compartment, firstly checking whether water leaks from the bottom of the vertical load bearing body 4, and if water leaks, readjusting the sealing gasket 11 to ensure that no leakage occurs;
step 3, stopping water injection when the bottom of the piston 8 is just in contact with the water surface and the top is just at the top position of the vertical load bearing body 4, erecting a bearing steel plate 121 and a hydraulic servo jack 122 at the same time as shown in fig. 5, arranging four pull rods 10 in each partition area at four corners of the bearing steel plate 121 to ensure uniform stress, and arranging the hydraulic servo jack 122 at the center of the bottom of the bearing steel plate 121;
step 4, setting an initial value of the hydraulic servo jack 122 through the computer 12 until the initial value is just in contact with the bearing steel plate 121 to bear force, and ensuring that the piston 8 cannot slide downwards;
step 5, filling a predetermined amount of soil into the box body 1, compacting until the whole model box is filled, and recording the initial filling height H, namely the distance between the top surface of the filling and the top surface of the vertical load-bearing body 4;
step 6, recording the initial water level of each water outlet pipe 7 after the soil filling is finished;
step 7, simulating the excavation process of a tunnel at the lower part of the soil body, controlling the unloading rate of the hydraulic servo jack 122 through the computer 13 to drive the pull rod 10 to move, so as to drive the piston 8 to slowly move downwards, so that the local soil body moves, the rest part keeps the original position, and the relative movement in the soil is resisted by the shear strength of the soil body, so that the soil body is compressed and deformed, and a soil arch effect is generated;
step 8, observing the water level change of the water outlet pipe 7, and reading the height difference h of the water levels of different compartmentsiThe soil pressure gamma z on the top of different compartments of the vertical load bearing body can be obtainedi＝ρghiRho is the density of water, gamma is the gravity of the filled soil, wherein i is 1-4;
9, calculating the vertical soil pressure gamma z of different compartmentsiBy the formula zi＝ρghiThe thickness z of the falling soil body of different compartments is obtained by inverse calculation of the gammaiFurther, the height H of the soil arch can be obtainedi＝H-ziAnd connecting the soil arch action areas at the tops of different compartments into a smooth curve, namely the action range of the soil arch effect, wherein i is 1-4.
The embodiments described in this specification are merely illustrative of implementations of the inventive concepts, and the scope of the invention should not be considered limited to the specific forms set forth in the embodiments, but rather the scope of the invention includes equivalent technical means that can be conceived by those skilled in the art based on the inventive concepts.

Claims (8)

1. A test device for judging the acting range of the soil arch effect of the top surface of an underground structure is characterized in that: comprises a hollow model box (1) and a vertical load-bearing body (4) arranged in the model box (1);
the periphery and the bottom of the vertical load bearing body (4) are formed by splicing steel plates, the splicing position is subjected to sealing treatment, the inner space of the vertical load bearing body (4) is uniformly divided by n-1 partition plates (6) with equal thickness to form n compartments, n is at least 2, and the partition plates (6) are tightly connected with the inner wall of the vertical load bearing body (4); each compartment is provided with a pull rod type piston (8) which is matched with the compartment and can slide up and down in the compartment along the inner wall, the pull rod type piston (8) consists of a piston (8) and a pull rod (10), the pull rod (10) is installed at the bottom of the piston (8) and sequentially penetrates through the vertical load bearing body (4) and the model box (1) and is provided with an extension section, the lower end part of the pull rod (10) is provided with a load device (12), the load device (12) comprises a bearing steel plate (121) and a hydraulic servo jack (122), and the bearing steel plate (121) is fixedly installed on a telescopic rod of the hydraulic servo jack (122) and moves up and down along with the telescopic rod in the vertical direction; the pull rod (10) is in plane contact with the bearing steel plate (121); the hydraulic servo jack (122) adopts a hydraulic oil cylinder to load or unload and transmits force to the pull rod type piston (8) through a bearing steel plate (121) to realize the up-and-down movement of the piston (8); the hydraulic servo jacks (122) uniformly control loading and unloading rates through an external computer (13); the bottom of each compartment is provided with a hole (5) with the same diameter; the bottom of the model box (1) is provided with a through hole (3) matched with the hole (5) corresponding to the hole (5) of the vertical load bearing body (4); the outer transparent outlet pipe (7) that has the scale of hole (5), outlet pipe (7) with vertical load body (4) intercommunication and constitute U type linker, outlet pipe (7) with vertical load body (4) sealing connection.
2. The test device of claim 1, wherein: the hole (5) department be equipped with connecting steel pipe (9), connecting steel pipe (9) outwards be equipped with the extension section along through-hole (3) of model box (1) bottom of the box from hole (5) of vertical load (4) bottom, connecting steel pipe (9) with outlet pipe (7) detachable connection.
3. The test device of claim 2, wherein: the connecting steel pipe (9) is in threaded connection with the water outlet pipe (7).
4. The test device of claim 1, wherein: four foot stands (2) are arranged at four angular points of the bottom of the model box (1).
5. The test device of claim 2, wherein: and the connecting steel pipe (9) is hermetically welded with the hole (5).
6. The test device of claim 1, wherein: the contact part of the pull rod type piston (8) and the inner wall of the compartment is wrapped by a sealing ring.
7. The test device of claim 1, wherein: the maximum load of the hydraulic servo jack is 1t, the maximum stroke is 400mm, and the maximum jacking speed is 60 mm/min.
8. The test device of claim 1, wherein: the bearing range of the bearing steel plate (121) cannot deform under the action of the load of at least an upper area; the hydraulic servo jack is positioned at the right center of the lower part of the bearing steel plate (121).
CN201921193182.3U 2019-07-26 2019-07-26 Test device for judging top surface soil arch effect action range of underground structure Withdrawn - After Issue CN211113791U (en)

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Application Number Priority Date Filing Date Title
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110468885A (en) * 2019-07-26 2019-11-19 浙江工业大学 A kind of experimental rig and its test method determining underground structure top surface soil arching effect sphere of action

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110468885A (en) * 2019-07-26 2019-11-19 浙江工业大学 A kind of experimental rig and its test method determining underground structure top surface soil arching effect sphere of action
CN110468885B (en) * 2019-07-26 2023-11-10 浙江工业大学 Test device and test method for judging soil arch effect action range of top surface of underground structure

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