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深部硬岩巷道围岩板裂破坏试验研究进展与展望

Research progress and prospect of laboratory test of rock spalling  in deep hard rock roadway

  • 摘要: 深部硬岩巷道及隧道围岩开挖后易诱发大致平行开挖面的板裂或层裂破坏现象,严重影响深部工程的稳定和安全。板裂现象的形成不仅与开挖前深部围岩岩性、所处应力环境有关,还与巷道开挖过程中围岩所经历的应力路径密切相关。室内试验是研究深部围岩板裂破坏的一种重要方法,而比照深部硬岩巷道开挖的应力条件和应力路径开展室内试验研究是获得板裂破坏特征和科学揭示板裂破坏形成机制的关键。根据室内试验研究所选的试样类型出发,从实心长方体试样板裂试验、含预制孔洞试样板裂试验以及“先加载后孔内卸荷”板裂试验三方面,重点介绍了板裂破坏室内试验设备发展情况和取得的研究进展,总结了板裂破坏室内试验研究中主要存在的问题和难题,提出了板裂破坏室内试验研究的未来发展趋势和方向:①研发与岩石性质相似的3D打印材料,构筑深部岩体大尺度巷道开挖模型试验试样;②研制能真实模拟巷道围岩应力条件和应力路径的大尺度、高吨位的真三轴试验系统,实现三维应力环境中巷道开挖过程模拟;③开发能显示围岩实时变形、裂隙和应力状态的监测技术和软件。在此基础上,开展室内巷道板裂破坏试验模拟,并结合数值模拟试验结果,总结板裂破坏特征和演化规律,获得板裂破坏具体量化指标,并建立含关键指标的板裂破坏判据,揭示深部围岩板裂破坏形成机制。

     

    Abstract: The excavation of a deep hard rock roadway or tunnel is easy to induce a spalling roughly parallel to the excavation surface of surrounding rock,which seriously affects the stability and safety of deep engineering. The formation of spalling are related to the lithology and stress environment of deep rock before excavation and the stress paths experienced by surrounding rock during roadway excavation. Laboratory test is an important method to study the spalling of deep surrounding rock,and the key to obtaining the spalling characteristics and scientifically revealing the formation mechanism of spalling is to perform laboratory test research according to the stress conditions and stress paths during excavation of deep hard rock roadways. The development of test equipment and the progress in spalling laboratory research were mainly introduced from three aspects according to the varied sample types used in the laboratory test on spalling:solid cuboid sample spalling test,sample with a prefabricated hole spalling test and “loading first and then interanal holing” spalling test. The problems existing in the laboratory similation tests on spalling were summarized,and the prospects of laboratory research into spalling were put forward:①Developing the 3D printing materials comparable to rocks for the large-scale roadway excavation model test of deep rock mass;②Developing a large-scale and high-toning true triaxial test system that can truly simulate the stress conditions and stress paths of surrounding rock,so as to simulate the roadway excavation process in a three-dimensional stress environment;③Developing the monitoring technology and software that can display the real-time deformation,fracture and stress state of surrounding rock. On this basis,to carry out the laboratory simulation test on roadway spalling combined with numerical simulation,summarize the characteristics and evolution law of spalling,obtain the specific quantitative indexes of spalling,establish a spalling criterion with key indexes,and reveal the formation mechanism of spalling in deep surrounding rock.

     

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