CN-121977944-A - Annular structure interface shear test device and method considering fluid viscosity

CN121977944ACN 121977944 ACN121977944 ACN 121977944ACN-121977944-A

Abstract

The invention discloses an annular structure interface shearing test device and method considering fluid viscosity, comprising a shearing cylinder, a loading plate, a test tube, a connecting tube, a displacement eduction tube, a reaction tube, a hollow jack and a pulling and pressing sensor, wherein a sample bin is formed by enclosing between the two loading plates, a loading bin is formed by enclosing between the loading plate and an end cover at the same side, stable sealing of fluids with different viscosities in a high-pressure environment is realized through a multi-channel matched sealing structure, and the actual annular structure interface forms of pile soil, pipe soil and other projects are precisely matched through an annular cavity structure, so that the annular structure interface direct shearing test of various rock soil samples with different consolidation pressures, different fluid viscosities and different hydraulic conditions can be realized, the interface occurrence environment is highly matched with the project site in the shearing process, the problem that the mechanical parameters of the annular structure interface containing viscous fluid cannot be accurately tested is effectively solved, and data support is provided for the research of the annular structure interface mechanical characteristics in the sea filling land, water-filled soft foundation treatment and other geotechnical projects.

Inventors

WANG ZUKUN
SONG LEI
Ding Shengyun
Feng Jihao
YANG WEIHAO

Assignees

中国矿业大学

Dates

Publication Date: 20260505
Application Date: 20260320

Claims (10)

1. The annular structure interface shear test device taking the viscosity of fluid into consideration is characterized by comprising a shear cylinder, an end cover, a base plate, a loading plate, a test tube, a connecting tube, a displacement eduction tube, a reaction tube, a hollow jack and a tension-compression sensor; the two loading plates are arranged in the shearing cylinder at intervals in parallel, an annular cavity between the two loading plates is a sample bin, and a cavity between the single loading plate and the end cover on the same side is a loading bin; The base plate is arranged between the end cover and the loading plate, the side part of the base plate is provided with a liquid injection hole and a sensor lead hole, the upper end surface and the lower end surface of the base plate are both provided with sealing grooves, and a base plate sealing ring is assembled in the sealing grooves; a sealing ring groove is formed in the side surface of the loading plate in a circumferential direction, a loading plate sealing ring is arranged in the sealing ring groove, a sensor mounting hole is formed in the vertical direction of the loading plate, and a mounting hole for a connecting pipe and a displacement eduction pipe to pass through is formed in the central position of the loading plate; The test tube is arranged in the sample bin, two ends of the test tube are respectively connected with an upper connecting tube and a lower connecting tube, and a connecting tube-loading plate sealing ring is arranged between the connecting tube and a mounting hole of the loading plate; the reaction tube is coaxially arranged outside the end cover, the reaction tube is coaxially connected with the test tube through the connecting tube, the hollow jack is coaxially sleeved outside the reaction tube and is fixed outside the end cover through a jack mounting hole of the end cover, and the tension and compression sensor is coaxially assembled on the reaction tube.
2. The interface shear test device for an annular structure taking into account fluid viscosity according to claim 1, wherein a pressure measuring hole is formed in the side portion of the wall of the shear cylinder, the pressure measuring hole is communicated with the sample bin, and a pressure monitoring element is arranged in the pressure measuring hole.
3. The annular structure interface shear test device considering fluid viscosity according to claim 1, wherein a connecting pipe-end cover sealing ring is arranged between the matching surfaces of the connecting pipe and the end cover, and a displacement lead-out pipe sealing ring is arranged between the displacement lead-out pipe and the mounting hole of the loading plate.
4. The interface shear test device for the annular structure taking fluid viscosity into consideration according to claim 1, wherein the locating pins of the backing plate are correspondingly inserted into the end face locating holes of the end cover and the loading plate, so that the coaxial locating of the backing plate is realized.
5. The device for testing the interface shear of the annular structure taking into consideration the viscosity of fluid according to claim 1, wherein the pull-press sensor is an S-shaped load sensor, and a signal output end of the pull-press sensor is electrically connected with an external data acquisition system.
6. The device for testing the interface shear of the annular structure taking into consideration the viscosity of fluid according to claim 1, wherein the end part of the displacement eduction tube is abutted against the measuring head of the displacement meter, and the signal output end of the displacement meter is electrically connected with an external data acquisition system.
7. The interface shear test device of annular structure taking into account fluid viscosity according to claim 1, wherein the sensor mounting hole of the loading plate is equipped with a pressure sensor, and the leads of the pressure sensor are led out to an external data acquisition system through the sensor lead holes of the backing plate.
8. A method of testing an interface shear test device of annular structure taking into account fluid viscosity according to any of claims 1 to 7, comprising the steps of: Preparing an annular structure body sample and a bulk material sample, carrying out saturation treatment on the sample, preparing a test fluid with target viscosity according to the formation fluid parameters of an engineering site, and measuring the fluid viscosity parameters; step two, preassembling a lower structure, namely horizontally erecting a lower end cover on a test support, sequentially installing a lower backing plate, preassembling a sensor and a lower loading plate of a sealing ring, and completing positioning and fixing of the lower structure of the shearing cylinder; Step three, assembling a main structure, namely coaxially installing a lower connecting pipe into the device, taking the structural body sample prepared in the step one as a test tube and connecting the test tube with the lower connecting pipe in a threaded manner, filling a bulk material sample into a sample bin in a shearing cylinder, enabling the bulk material sample to wrap the test tube to form an annular structure interface, sequentially installing an upper loading plate, an upper base plate and upper end covers, and completing fastening sealing of the shearing cylinder and the end covers at two ends; injecting the viscous fluid configured in the first step into the sample bin through a fluid inlet of a loading plate after the integral tightness detection of the device is completed, and maintaining the pressure until the fluid pressure in the sample bin reaches a preset value; Injecting hydraulic medium into an upper loading bin and a lower loading bin through liquid injection holes of a base plate for pressurizing, and monitoring the pressure of the loading bins in real time through a pressure sensor until the pressure reaches the preset consolidation pressure and keeps stable; step six, disassembling and resetting the device, namely grading and releasing pressure to the loading bin after the direct shear test is finished, grading and releasing pressure to the sample bin, discharging fluid and hydraulic medium in the device, and then sequentially disassembling the upper part of the sample, taking out the sample, and finishing cleaning and resetting the device.
9. The test method according to claim 8, wherein in the first step, the structural body sample is any one of a rock column, a concrete pipe and a steel pipe, and the bulk material sample is any one of an in-situ soil body and a crushed stone filler.
10. The test method according to claim 8, wherein the steps one to six are repeated, and test fluids with different viscosities, different consolidation pressures and different hydraulic parameters are replaced to obtain multiple groups of annular structure interface shear test data under different working conditions.

Description

Annular structure interface shear test device and method considering fluid viscosity Technical Field The invention relates to the technical field of geotechnical engineering interface mechanical property test, in particular to an annular structure interface shear test device and method considering fluid viscosity. Background The shear strength of the structural interface is a mechanical parameter of a core in geotechnical engineering design and construction, and accurate measurement of the shear strength of the interface is a key foundation for guaranteeing geotechnical engineering safety. In the construction engineering, the bearing capacity design of friction piles in weak stratum is highly dependent on the mechanical parameters of pile-soil interface, and the friction characteristics of freezing pipes and surrounding frozen soil directly determine the construction safety and cost control of the construction engineering in the mine well construction process. Under special working conditions such as sea filling and land making, offshore engineering, water saturation soft foundation treatment and the like, the stress transfer rule of the annular structure interfaces such as pile soil, pipe soil and the like is not only influenced by stratum stress, but also is obviously influenced by fluid parameters such as pore water pressure, fluid viscosity and the like. Therefore, the interface shear characteristics of various annular structures considering the viscosity of the fluid are studied in depth, and key theoretical support and data basis can be provided for the design and construction of the geotechnical engineering. At present, more technical schemes are formed in the industry aiming at experimental research of structural interface shear characteristics. For example, the invention patent with the publication number of CN108106949A and the name of a method for in-situ test of shear strength of a pile-soil interface and a symmetrical direct shear apparatus discloses a device capable of realizing direct shear test of an interface between a geosynthetic clay liner and other geotechnical materials, can accurately measure interface dislocation displacement, the invention patent with the publication number of CN105865939A and the name of a method for testing shear stress of a pile-soil interface, provides a real-time test scheme of shear stress of a pile-soil interface, realizes accurate reading of shear stress through a force measuring steel rod and a sensor, the invention patent with the publication number of CN118258704A and the name of a structure-soil interface shear characteristic tester and a shear characteristic acquisition method, provides an interface shear test device capable of simulating variable temperature and dynamic shear environments, and the invention patent with the publication number of CN114062107A and the name of a box shear device suitable for direct shear tests of cylindrical samples with different sizes and application thereof, and discloses a direct shear test device suitable for cylindrical soil samples with different sizes. The technical defects of the prior art are that firstly, the prior device adopts a traditional plane shear box structure, the dynamic sealing problem in the shear process is difficult to solve, the high-pressure fluid cannot be guaranteed not to leak in the shear process, therefore, the influence of different viscosity and different pressure fluids on the interface shear characteristics cannot be simulated, the actual occurrence environment of a structural interface in a saturated stratum cannot be restored, secondly, the prior shear box is of a plane structure, the shape effect of an annular structure interface such as pile soil and pipe soil cannot be simulated, the interface mechanical parameters obtained through test have larger deviation from engineering reality, thirdly, the prior device cannot flexibly adjust the fluid viscosity parameters, the formation fluid characteristics of different engineering sites are difficult to match, and the engineering applicability of test results is poor. Therefore, how to provide a new test device and method can effectively solve the industrial problems that the existing interface shear test device cannot realize stable sealing of high-pressure viscous fluid, cannot simulate the interface shape effect of an annular structure and has low matching degree between a test environment and an engineering site, and is the direction of research required by the invention. Disclosure of Invention Aiming at the problems in the prior art, the invention provides the annular structure interface shear test device and the annular structure interface shear test method considering the fluid viscosity, which can realize the accurate test of the mechanical parameters of the annular structure interface under different consolidation pressures, different fluid viscosities and different hydraulic conditions. In order to achieve the purpose, the techni