Field rock mass poisson ratio test method

Abstract

The invention discloses a field rock mass poisson ratio test method. The method comprises the steps of firstly digging a test flat hole in a mountain, drilling a cylindrical test piece on bedrock on the bottom surface of the test flat hole by utilizing a hollow drill bit, and symmetrically perforating test holes in the bottom of an annular groove at the periphery of the test piece; sleeving the test piece with an elastic steel lantern ring provided with a steel contact and a strain plate, connecting a strain plate test line and a resistance strain gauge, and calculating transverse deformation of the test piece by virtue of test; fixing the top surface of the test piece together with a test flat hole top plate sequentially through a pressure plate, a jack, a reducing connector steel plate, a combined force transfer rod and a hinge anchor, installing measuring points in bolt holes in two sides of the pressure plate and in the test holes in the bottom of the annular groove, and installing a dial indicator above the measuring point; calculating vertical deformation of the test piece after the load test; then calculating a corresponding transverse strain value and a vertical strain value, and calculating the poisson ratio of the test piece according to the transverse strain value and the vertical strain value. The field rock mass poisson ratio test method has advantages that the implementation method is simple and rapid, the measurement data is accurate and reliable, and the real condition of the rock mass can be comprehensively reflected.

Description

Technical field [0001] The invention relates to the deformation modulus of a rock mass in the construction of a water conservancy project, in particular to a method for testing the Poisson's ratio of the rock mass on site. Background technique [0002] Poisson's ratio refers to the ratio of the absolute value of the transverse strain to the vertical strain when a material is subjected to unidirectional compression (or tension). The deformation (or elasticity) modulus of the rock mass in the construction of water conservancy projects is an important design parameter of the project. This parameter is to obtain the pressure and the corresponding deformation value through the deformation test of the rock mass, and then perform the deformation modulus and elastic modulus of the rock mass. For calculation, the calculation formula is shown in formula 1.1. [0003] Formula 1.1 [0004] In the formula: E —— deformation modulus or elastic modulus, MPa; in f...

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Problems solved by technology

[0012] As we all know, Poisson's ratio is directly related to rock strength, weathering degree, and development of joints and fissures. In indoor rock Poisson's ratio test, strain gauges are pasted on the specimen. The pasting method, etc. will affect the measurement data, and the measurement value cannot be directly verified

If the Poisson's ratio of the rock mass can be measured from the site where the rock mass deformation test is carried out, the value will be more reasonable. However, since there is no good method to measure the lateral deformation of the rock mass on site, the indoor rock test method will be limited by The site environment and conditions are difficult to achieve

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