单面卸载条件下深埋圆形洞室围岩岩爆的试验模拟研究  

Experimental simulation of rockburst in the surrounding rock of a deep circular cavern induced by single-side unloading

作　　者：焉兆熙 刘科伟[1] 杨家彩[1] 郭腾飞 宋锐涛 王培宇 YAN Zhao-xi;LIU Ke-wei;YANG Jia-cai;GUO Teng-fei;SONG Rui-tao;WANG Pei-yu(School of Resources and Safety Engineering,Central South University,Changsha,Hunan 410083,China;School of Civil Engineering,Sun Yat-sen University,Zhuhai,Guangdong 519082,China)

机构地区：[1]中南大学资源与安全工程学院,湖南长沙410083 [2]中山大学土木工程学院,广东珠海519082

出　　处：《岩土力学》2024年第8期2437-2449,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.51974360)。

摘　　要：为深入研究深部洞室开挖诱发邻近既有洞室围岩岩爆的发生过程和机制,采用真三轴电液伺服诱变试验系统对具有强岩爆倾向性的花岗岩开展试验研究,模拟500 m的三维应力状态。通过卸载洞室围岩单侧荷载模拟邻近洞室开挖,在围岩应力重分布作用下最终诱发岩爆,试验中借助监测设备实时观测洞壁的破坏现象。试验结果表明:(1)在单面卸载条件下,岩爆过程可分为6个阶段,即卸载后的应力重分布、准备期、第1轮岩屑弹射和剥落、平静期、第2轮岩屑弹射和剥落、剧烈破坏;(2)在卸荷作用的影响下,洞壁岩爆呈现出明显的时空特征和非对称性,表现为卸荷后洞室顶底部率先出现明显裂纹,在随后的持续加载过程中,远离卸载面一侧发生剧烈岩爆并形成沿轴向贯通的V型槽;(3)基于定义的滞后效应系数可知,与三向加载岩爆相比,单面卸载下的洞室岩爆具有更强的突然性,且极易导致洞室的整体垮塌。为预防该类型岩爆,邻近洞室开挖时应及时对既有洞室远离卸载面一侧进行支护和加固处理。To further study the occurrence process and mechanism of rockburst induced by excavation of deep caverns,the true triaxial electro-hydraulic servo mutagenesis test system was used to carry out experimental research on granite with strong rockburst tendency and simulated the three-dimensional stress state at a depth of 500 meters.The excavation process near the cavern was simulated by unloading the unilateral load of the surrounding rock,and ultimately inducing rockbursts due to stress redistribution of the surrounding rock.In the experiment,monitoring equipment observed real-time tunnel wall failures.The test results revealed:(1)the rockburst process under single-side unloading can be divided into six stages-stress redistribution post-unloading,preparation period,initial cuttings ejection and spalling,calm period,secondary cuttings ejection and spalling,and severe damage;(2)Rockbursts in the cave wall exhibited distinct temporal and spatial characteristics and asymmetry under unloading influence,with cracks initially appearing at the cave roof's base post-unloading,followed by severe rockbursts on the side opposite the unloading surface,forming a V-shaped trough along the axis during subsequent loading;(3)The defined hysteresis effect coefficient indicated that compared to rockbursts under three-direction loading,single-side unloading-induced rockbursts displayed greater abruptness and were more prone to cavern collapse.To mitigate such rockbursts,support and reinforcement measures should be implemented on the existing cavern side opposite the unloading surface when excavating adjacent caverns.

关 键 词：试验模拟 邻近洞室开挖 岩爆 真三轴试验系统 单面卸载 

分 类 号：TU45[建筑科学—岩土工程]