Automatic device for indoor test bed coefficient

Abstract

The invention discloses an automatic device for indoor testing of bed coefficient, which comprises the following parts: an axial pressure device; The annular pressure plate and the upper permeable plate are respectively connected to the outer dowel and the inner dowel, which are connected to the axial pressure device; the shear controller is used to drive the lifting platform to move up and down; the surrounding pressure controller is passed through The confining pressure pipeline communicates with the pressure chamber, and a confining pressure sensor is arranged on the confining pressure pipeline; the back pressure controller is connected with the upper permeable hole of the annular pressure plate through the top pipeline; the back pressure sensor is set on the top pipeline; the pore pressure sensor is connected to the The inside of the sample is connected; the data collector; the computer control system is respectively connected with the data collector, the shear controller, the surrounding pressure controller and the back pressure controller.

Description

technical field [0001] The invention relates to the technical field of geotechnical engineering testing, in particular, to an indoor simulation site in situ K 30 Geotechnical test automation device for testing subgrade coefficient. Background technique [0002] In 1867, when Winkler was studying the superstructure of railway embankment, he put forward the assumption of elastic foundation: the pressure intensity P on any point on the foundation is proportional to the settlement s of the foundation at that point, expressed as: K=P / s. In engineering, the ratio of the pressure intensity P to the settlement s (0.125cm) when the pressure plate with a diameter of 30cm produces 0.125cm settlement is called the standard bed coefficient K 30 . As a parameter of the compressibility of the foundation, the subgrade coefficient was first applied in the calculation of beams and slabs on elastic foundations, and then applied to the internal force analysis of structures bearing lateral loa...

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Problems solved by technology

However, due to the water head saturation method, there is insufficient saturation for soft clay; limited by the boundary conditions of the laboratory test, it is impossible to measure the shear stress of the axially loaded side wall of the sample, which affects the accuracy of the bed coefficient

[0008] Defects existing in the existing indoor triaxial method: 1) The actual compression settlement depth exceeds the height of the sample, so that the measured settlement s is too small; 2) The axial load σ of the sample cannot be measured 1 The generated side wall shear stress f, resulting in the specimen axial load P (P = σ 1 -f) is too large

The above reasons make the test results and K 30 The comparison deviation is too large to be directly adopted by the design

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