Hollow sample making device

Abstract

The invention relates to a hollow sample making device, comprising a pressure head mechanism, two transmission mechanisms and a controller, wherein the pressure head mechanism is composed of an upper die head, a lower die head and an outer die; the transmission shafts of the two transmission mechanisms are connected with a screw rod in a symmetrical manner; the screw rod is connected with nut pieces which respectively fasten the lower die head and the upper die head by bolts; the nut piece is provided with a position sensor; and the transmission mechanism and the position sensor are connected with the controller via cables. In the invention, a bidirectional compaction structure in which the upper and lower die heads simultaneously apply pressure on the outer die is adopted in the sample making process; and a die adopts an embedded die cavity structure, and the size and model of the die can be changed according to the samples. The sample making device in the invention has scientific design, simple structure, convenient operation and use and high cost performance, and fundamentally solves the difficult problems of scale material feeding and automatic demoulding in the preparation process of making samples, thus realizing mechanical operation and batch production and having the advantages of rapidness, efficiency, low cost, good sample repeatability and strong comparability; and in addition, the sample making device can make samples in the geotechnical detection field, and popularizes preparation for various test samples similar to ground.

Description

Technical field [0001] The invention relates to a hollow sample preparation instrument, which is a geotechnical sample preparation instrument. Background technique [0002] As an ancient building material, the strength of soil is actually the measurement of shear strength. Experimental soil mechanics is one of the four pillars of the development of modern soil mechanics. With the development of science, a large number of indoor methods for measuring the shear strength of soil have emerged. Compared with other test methods, the hollow cylindrical torsional shear instrument has many advantages that other testing instruments do not have: the principal stress in three directions can be independently applied to the sample, and the shear can be applied to the sample by applying torque and controlling torsional displacement through the piston rod. In addition, the principal stress in the three directions can be changed independently, so that the direction of the principal stress ...

AI Technical Summary

Problems solved by technology

However, the preparation of the hollow sample required for the test is very troublesome, which greatly limits the popularization and application of this geotechnical instrument.

[0003]Predecessors have done a lot of research work on the preparation of hollow samples, but the methods and principles are mostly classical compaction tests. The defects of the developed instruments are summarized as follows:( 1) Sample preparation takes a long time, it is difficult to demould, and the efficiency is low; (2) The degree of automation is very low, basically relying on manual work; (3) The density and water content are not uniform; it is difficult to prepare samples with higher density; (4) ) The flatness of the sample is low; (5) The accuracy cannot be guaranteed, resulting in great differences in test results, poor comparability and repeatability of test results; (6) Severe noise pollution and strong vibration seriously affect the normal work of others

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