Method for directly determining long-term strength of rock mass by quick creep test

Abstract

The invention provides a method for directly determining long-term strength of a rock mass by quick creep test. The method comprises the following steps of (1) performing graded loading creep test on the studied rock mass, so as to obtain a graded loading creep test curve of the rock mass; (2) according to the graded loading creep test curve, judging the minimum load value of viscous plasticity deformation; (3) for the test curve with viscous plasticity deformation, using a creep deformation formula to fit, so as to obtain the viscous plasticity deformation rate; (4) according to the relationship between the viscous plasticity deformation rate and the stress level, extrapolating to obtain the stress when the viscous plasticity deformation rate is 0, namely the long-term strength. The method has the advantages that the creep test time can be shortened, the long-term strength of the rock mass can be directly determined by the graded loading creep test curve, the artificial judging of inflection points is not needed, and then a reliable basis is provided for the long-term safety evaluation of the rock mass structure.

Description

technical field [0001] The invention relates to a method for directly determining the long-term strength of rock mass from the rapid staged loading creep test curve of rock mass, and the method is mainly applicable to the field of long-term safety of rock mass engineering. Background technique [0002] With the rapid development and construction of projects in the fields of water conservancy and hydropower, energy, and transportation, the long-term safety of rock mass structures such as dam foundations, tunnels, and slopes involved in large-scale projects under load is particularly important. In order to evaluate the long-term safety of rock mass structure, one of the important parameters is the long-term strength of rock mass. In recent years, abundant research results have been obtained in the field of determining the long-term strength of rock mass, and these results have played a certain role in the long-term safety evaluation of rock mass structures. [0003] The deter...

AI Technical Summary

Problems solved by technology

The above three methods can all determine the long-term strength of rock mass in theory, but the workload of determining the long-term strength is large and the accuracy is often not high

On the one hand, the above method requires processing the creep test curve, which is complicated, requires a lot of work, and will introduce processing errors; on the other hand, the above methods all need to manually judge the position of the inflection point of the test curve. It is difficult to judge and the judgment error is large; in addition, the latter two methods can only determine the range value of the long-term strength, but cannot obtain the long-term strength determination value

[0005] In actual engineering, the long-term strength is often determined according to the results of the rock mass creep test, and the creep test is carried out in a staged loading manner, so the entire creep test lasts a long time, is greatly affected by environmental factors, and costs a lot

Errors will be introduced when superimposing the graded loading curves, and the artificial judgment of the inflection point of the curve will further accumulate errors, resulting in a large error in the determined long-term strength

In addition, for rock masses with low rheology, the inflection point of the creep curve is very difficult to determine, which also brings difficulties to the determination of long-term strength