脆性岩石热-水-力-化学(THMC)耦合裂纹扩展速率测试新方法

A new measurement method of crack propagation rate for brittle rock under THMC coupling condition

提出连续测量脆性岩石热-水-力-化学(THMC)耦合裂纹扩展速率的新型导电碳膜电测法。利用自行设计的耦合加载系统,连续测量不同温度下预制红砂岩试件THMC耦合裂纹扩展速率。结果表明:随着温度的增加,红砂岩试件起裂时间缩短,裂纹扩展速率和加速度增大。通过能量法计算的理论结果与试验结果吻合较好,验证THMC耦合裂纹扩展速率导电碳膜电测法的有效性。该方法能克服传统电法不能连续测量裂纹扩展速率以及光学法和声法不能测量多场耦合裂纹扩展速率的缺点,为THMC耦合作用下深部岩体工程的安全评估和止裂设计提供重要的理论依据。

A new electrical method of conductive carbon-film(with waterproof and anticorrosion ability)was proposed to continuously measure crack propagation rate of brittle rock under THMC coupling condition.A self-designed coupling testing system was used to conduct THMC coupling fracture tests of the pre-cracked red sandstone specimens(where the temperature is only changed)by this new electrical method of conductive carbon-film.Calculation results obtained by the energy method coincide well with the test results.And the higher the temperature is,the earlier the crack is initiated and the larger the crack propagation rate and accelerated velocity are,which can prove the validity of the new electrical method.This new electrical method has advantages of continuously measuring crack propagation rate over the conventional electrical,optical and acoustic methods,and can provide important basis for safety assessment and cracking-arrest design of deep rock mass engineering.