软岩蠕变理论及其工程应用

地下工程的施工经常遇到软岩。这类岩体抗压强度较低，具有明显的流变特性，蠕变变形量较大，常造成支护的失稳和破坏。在分析地下工程的稳定性或对地下结构设计时，应充分考虑这一特性，按流变力学理论进行分析和设计。通过现场取样，采用自行研制的重力杠杆式岩石蠕变试验机，并配备三轴压力室，对泥岩进行了三轴蠕变试验。试验结果表明，泥岩的蠕变具有非线性。根据试验结果，建立了泥岩的非线性蠕变方程。根据上述非线性蠕变方程，分析了围岩的应力场和位移场，并对不同支护强度和应力状态下的蠕变变形进行了系统的分析。理论研究结果表明，控制围岩过量蠕变变形的根本途径是改善围岩应力状态，适当提高锚杆或锚索的初始预应力，从而为有效控制深部开采时围岩的有害变形提供了理论依据。

CREEP THEORY OF SOFT ROCK AND ITS ENGINEERING APPLICATION

The construction of underground engineering often encounters soft rocks,whose compressive strength is lower,with obvious characteristics of rheology. The amount of creep deformation is big enough to cause failure of support. The characteristics of rheology should be taken into consideration for analysis of stability or design of underground engineering. Triaxial creep test is made for mudstone with the authors-developed gravitation lever style rock creep test machine and triaxial pressure cell. Testing results show that the creep of mudstone is of nonlinearity. On the basis of testing results,nonlinear creep equation is established. According to the equation,the stress and displacement field of surrounding rocks may be analyzed. Theory research result shows that the basic way to control excessive creep deformation is to improve the stress state of surrounding rocks,and properly increase prestress of bolt or cable,so that the theory basis is provided for effective control of the harmful deformation of surrounding rocks in deep mining.