复杂应力路径下的花岗岩洞室开挖损伤区研究  

Excavation damage zones in granite cavern under complex stress paths

作　　者：王贵宾[1] 刘桓兑 唐明豪 杨春和[1] 陈世万 WANG Gui-bin;LIU Huan-dui;TANG Ming-hao;YANG Chun-he;CHEN Shi-wan(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Science,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Zhejiang Academy of Emergency Management Sciences,Hangzhou,Zhejiang 310012,China;College of Resources and Environmental Engineering,Guizhou University,Guiyang,Guizhou 550003,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]浙江省应急管理科学研究院,浙江杭州310012 [4]贵州大学资源与环境工程学院,贵州贵阳550033

出　　处：《岩土力学》2024年第9期2539-2553,共15页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42272321,No.42162027)。

摘　　要：在储库的建设与运行过程中,复杂的应力路径是控制围岩损伤的主要因素。然而在围岩的损伤区研究中,应力路径仍未得到充分考虑,特别是忽略了主应力轴旋转在围岩损伤中的作用。基于岩石扭剪仪开展岩石主应力轴旋转试验,利用断裂力学理论对裂隙的尖端应力场进行了分析。结果表明,应力旋转会提高裂隙尖端的拉应力以促进裂隙的进一步发育,从而导致岩体强度的降低,且降低幅度与旋转角度呈明显的正相关关系。基于上述结果提出了一种考虑应力旋转的损伤演化表征法,在岩体最大偏应力超过第一次起裂应力后,对主应力轴任意方向的旋转角度进行累加,得到累计有效旋转角度。利用其随深度变化规律实现开挖损伤区(excavation damage zones,简称EDZS)的圈定,同时利用损伤区的最大深度和超过第2次起裂应力的偏应力范围划定剥落区。该方法综合考虑了应力路径中主应力的幅值与旋转角度的变化,更加全面地反映了围岩损伤演化机制,并通过Mine-by隧道数值模型与现场监测数据的对比进行了有效性验证。本研究可以为理解围岩损伤机制和预测围岩损伤范围提供新思路。During the construction and operation of storage reservoirs,the complex stress path plays a crucial role in controlling the damage to the surrounding rock.However,the current study of surrounding rocks lacks a comprehensive consideration of stress paths,especially in terms of the principal stress axis rotation.In this research,a test on rock principal stress axis rotation was conducted using the rock torsion shear apparatus,and the stress field at the fracture tip under stress rotation was analyzed employing fracture mechanics theory.The findings suggest that stress rotation increases the tensile stress at the fracture tip,accelerates fracture propagation,and leads to a notable decrease in rock strength.A methodology for characterizing damage evolution considering stress rotation is proposed based on these findings.Once the maximum differential stress exceeds the first cracking stress,the rotation angles in each direction of the principal stress axis are summed to obtain the cumulative effective rotation angle.This angle is then used to delineate the excavation damage zones(EDZs)based on its variation with depth.The spalling zone is identified using the maximum depth of the damage zone and the range of differential stress that exceeds the second cracking stress.The method integrates the amplitude and rotation angle of the principal stresses to offer a more comprehensive response to the surrounding rock damage evolution mechanism.The validity of this approach is confirmed through a comparison between the numerical model of the Mine-by tunnel and the monitoring data.This study provides novel insights into the damage mechanism of surrounding rock and the prediction of the surrounding rock damage range.

关 键 词：应力路径 开挖损伤区(EDZ) 花岗岩 起裂应力 应力旋转 

分 类 号：TU452[建筑科学—岩土工程]