On-site in-situ triaxial consolidation drainage and consolidation non-drainage shearing device

Abstract

At least two sets of fluid cylinders perpendicular to the axis are evenly distributed in the circumferential direction of a cylinder body, a friction plate is connected with piston rods of the fluid cylinders, and a connecting hole connected with a drill rod and a fluid inlet and outlet hole communicated with the fluid cylinders are formed in the top end of the cylinder body. The friction plate is provided with an annular groove I for fixing the permeable stone, annular tables are arranged on the two sides of the friction plate respectively, embedding holes for embedding the pore water pressure gauges are formed in the outer circumferences of the annular tables, threading holes I communicated with the embedding holes are formed in the top end of the friction plate, cables of the pore water pressure gauges penetrate through the threading holes I, and permeable holes communicated with the permeable stone are further formed in the two ends of the friction plate. The fluid cylinder pushes the friction plate to penetrate into the rock-soil body, so that the shear strength index can be quickly obtained, the consolidation drainage test and the consolidation non-drainage test can be flexibly switched through the water permeable holes in the closed friction plate and the non-closed friction plate, and the device has the advantages of being simple in structure, small in soil body disturbance, large in test stroke, high in result precision, wide in application range and capable of being flexibly switched.

Description

technical field [0001] The invention belongs to the technical field of construction geotechnical field detection, and in particular relates to an on-site in-situ triaxial consolidation drainage and consolidation system with simple structure, small soil disturbance, large test stroke, high result accuracy, wide application range and flexible conversion. Undrained shearing device. Background technique [0002] In traditional geotechnical engineering projects, the shear strength of rock and soil is an important evaluation parameter in engineering design and construction. At present, indoor shear experiments and in-situ shear tests are usually used to determine the shear strength of rock and soil. In indoor tests, drilling rigs are often used to drill holes, and then undisturbed or slightly disturbed geotechnical samples are taken from the holes, and then the soil samples in the corresponding state are obtained by indoor direct shear consolidation quick shear, direct shear quick...

AI Technical Summary

Problems solved by technology

Indoor tests often use drilling rigs to drill holes, and then take undisturbed or slightly disturbed rock and soil samples from the holes, and then use indoor direct shear consolidation fast shear, direct shear fast shear, triaxial and other test methods to obtain the soil in the corresponding state. body shear strength index; however, only the shear test of the soil remodeling sample can be carried out, which cannot fully represent the shear strength under the original structural characteristics of the engineering point. Even if the original soil sample is used for the test, it will not be possible Avoid experiencing disturbances such as stress release and reloading, resulting in the indicators obtained after the soil stress is released are often different from the actual conditions, and the soil extraction process also takes a long time

The in-situ shear test is carried out in situ at the site to be tested. Since the natural state of the soil is basically maintained, it is more representative than the indoor test; however, the existing in-situ shear device uses a steel diaphragm Such mechanical systems not only have complex structure and high failure rate, but also are restricted by the stroke of piercing the soil, thus affecting the accuracy of in-situ testing

[0003] In the prior art, there is a retractable scissor-shaped shearing plate, which is put into the drill hole by retracting the shearing plate, and then uses the self-weight of the shearing plate, the counterweight or the downward thrust exerted by the ground to make the shearing plate The cutting plate is opened and inserted into the hole wall of the borehole, and finally the soil sample is sheared by pulling the shearing plate on the surface using the loading system to obtain the shear strength characteristics of the in-situ soil sample; although it can significantly increase the penetration of the soil However, when the shear plate is opened, the soil sample will be disturbed, and the depth or pressure of the penetration is uncontrollable, and the thin shear plate can only contact and shear part of the soil sample, and it is difficult to obtain the soil of the complete borehole wall. sample shear performance

In addition, the shearing probe is placed on the lower end of the drill pipe or tie rod through the ear hook, and the L-shaped and box-shaped shearing plate is moved to penetrate the soil by setting a two-way piston cylinder on the shearing probe, and then the hydraulic hollow The jack drives the drill pipe or pull rod to move upward to shear the soil to obtain parameters; although the depth or pressure of the penetration is controllable, and the stroke of the penetration into the soil is large and stable, but because the two-way piston cylinder is vertically connected by a flexible steel belt, the piston When the normal pressure is generated, since there is no guidance in the horizontal direction, it is easy to be deflected when the properties of the left and right soil samples are different, which will affect the accuracy of the measurement; and because the shear probe is hung at the lower end of the tie rod, the shear probe is placed in the borehole The shaking will cause disturbance to the soil

In addition, there is also a structure that uses a hydraulic device to press the static penetration probe rod into the rock and soil, and obtains parameters and calculates the undrained shear resistance through the resistance sensor at the tip of the static penetration probe rod and the resistance sensor on the side. Strength, degree of consolidation, etc.; although it can solve the stroke problem, it can only be used for consolidated undrained (CU) shear tests due to its structural limitations, but it is powerless for consolidated drained (CD) shear tests, and additional The characteristic device is tested again, not only the operation is cumbersome, but also the test speed is slow

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