断续节理岩石中开挖附近扰动区失稳行为的实验  

Experimental study of failure behavior of disturbed zone around an opening in non-persistent jointed rock masses

作　　者：林鹏[1] 黄凯珠[2] 唐春安[3] 周维垣[1] 

机构地区：[1]清华大学水利水电工程系,北京100084 [2]香港理工大学土木与结构工程系 [3]东北大学岩石破裂与失稳研究中心,沈阳110006

出　　处：《清华大学学报（自然科学版）》2003年第8期1108-1111,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金资助项目(59939190);香港理工大学研究基金(PolyU5050/99E);中国博士后科学基金资助

摘　　要：目的是用实验方法研究在一定加载条件下,断续节理岩体中裂纹萌生、扩展、贯通机制及开挖扰动区的破坏行为。实验试样用作者配制的模拟材料制成。利用作者设计的小型开挖系统,在双轴加压下,当轴向压力达到峰值力的75%时,保持径向加载和轴向加载的比值λ恒定,模拟开挖过程,并用数码摄像机全程跟踪开挖过程。实验结果显示开挖附近断续节理滑移、贯通以及扰动区的变形决定了巷道的失稳行为和最终的破坏模式;开挖过程明显影响着内部扰动区和外部压缩区的变形。开挖后,内部扰动区的变形大于外部压缩区;开挖后,继续保持λ恒定时,应力和变形作为时间的函数逐渐释放,并且造成一些节理的滑动和微破裂的相互作用;λ越大,则巷道破坏的时间越短。A small excavating system was used to experimentally investigate crack initiation, propagation and coalescence mechanisms and failure behavior around an opening in nonpersistent jointed rock masses with biaxial loading. The specimens were made of modelling material with holes drilled to various stress levels to simulate underground excavation. The opening process was then monitored by a digital video camera. When the applied axial loading reached about 75% of the peak axial loading, the ratio, λ, of the lateral loading to the axial loading remained constant. The experimental results showed that the final failure behavior and modes around the opening were dominated by sliding along the joints, by coalescence between the joints and the opening, and by the strain in the disturbed zone around the opening. The deformation of the inner disturbed zone was greater than that of the outer compressed zone during the postexcavation process. Release of the stresses during postexcavation increases the interaction between microfractures and causes preexisting joints to slip when λ is constant. The specimen failure stress decreased with increasing values of λ.

关 键 词：结构实验 断续节理岩体 开挖扰动区 裂纹扩展 失稳行为 地下工程 裂纹贯通 巷道破坏 

分 类 号：TU941[建筑科学—建筑技术科学] TU457