Box type sampling shear strength testing method

Abstract

The invention discloses a box type sampling shear strength testing method, which comprises: a, a positioning operation, wherein the positioning operation comprises a horizontal positioning operation and a vertical positioning operation; and b, a shear strength measurement operation, wherein the positive rotation starting of the drive motor of a drive mechanism is controlled by a control circuit, a cross plate test assembly is driven to rotate to preset the angle value, the torque value applied on the cross plate is real-timely collected through the control circuit during the rotation process and the corresponding rotation angle value is combined, and the curve map of the shear stress along with the rotation angle change is output and displayed; and after the peak value appears for 1 min in the curve map, the experiment is stopped and the peak value is determined as the shear strength value of the clay to be tested. According to the present invention, the box type sampling shear strength testing method relates to, but is not limited to clay test equipment; and with the box type sampling shear strength testing method, the drawbacks in the prior art can be effectively overcome, the shear strength test of the soft clay with the high water content can be achieved, and the precision of the final test result can be effectively ensured.

Description

Technical field [0001] This application relates to but is not limited to clay testing equipment, especially a box-type sampling shear strength testing method. Background technique [0002] In the prior art, the cross plate shear test is a test for measuring the undrained shear strength and sensitivity of saturated soft clay soil with a cross plate. It is one of the original tests; specifically, the cross plate head is pressed by a borehole. Into the soft soil at the bottom of the hole, rotate at a uniform speed, and measure the torque required for rotation through a certain measuring system until the soil is broken, thereby calculating the shear strength of the soil. During the above-mentioned specific testing process, the cohesive soil to be tested needs to provide sufficient supporting reaction force to ensure the smooth progress of the test. [0003] At present, in the deep ocean environment, shallow soil layers are soft clays with high water content. The shear strength of this...

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Problems solved by technology

However, in the specific test process of the above-mentioned shear strength, the shear strength of the shallow soft clay cannot provide sufficient supporting reaction force for the test equipment of the conventional in-situ cross plate shear test; The plate shear test equipment cannot realize the shear strength measurement of the above shallow soil layer

[0004] Based on this, those skilled in the art also try to measure the above-mentioned soft clay with high water content in other ways; specifically, a certain column of clay to be tested is taken from the box sampler through a plastic tube, and the clay is limited by the wall of the plastic tube. To avoid large-scale flow, and then measure the shear strength of the above-mentioned clay to be tested in the plastic tube; the above-mentioned test process has the following disadvantages: the test is a manual point-by-point test, and only the peak value of the shear strength can be recorded. Continuous tracking test cannot be realized; the test is a vertical orientation test, horizontal positioning cannot be realized, and multi-point testing on the same plane cannot be realized, and the test result error is large; the string sampling operation of plastic pipe involves secondary sampling operation, and the clay to be tested The disturbance is large, which affects the accuracy of the final test result

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