高边墙洞室劈裂破坏机制的试验与理论及计算分析研究  

Experimental,theoretical and computational analysis on splitting failure mechanism of high sidewall caverns

作　　者：李帆 张强勇[1] 向文 丁炎志 薛天恩 张瑞新 LI Fan;ZHANG Qiangyong;XIANG Wen;DING Yanzhi;XUE Tianen;ZHANG Ruixin(Research Center of Geotechnical and Structural Engineering,Shandong University,Jinan,Shandong 250061,China;School of Qilu Transportation,Shandong University,Jinan,Shandong 250002,China)

机构地区：[1]山东大学岩土与结构工程研究中心,山东济南250061 [2]山东大学齐鲁交通学院,山东济南250002

出　　处：《岩石力学与工程学报》2023年第7期1662-1679,共18页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金项目资助(42172292,41772282);山东能源集团揭榜挂帅项目资助(SNKJ2022A01-R26)。

摘　　要：高边墙洞室的劈裂破坏现象已成为影响大型水电站地下厂房施工开挖安全的重要因素。为弄清劈裂破坏现象的形成机制,以瀑布沟水电站地下主厂房高边墙洞室为研究背景工程,开展真三维高地应力条件下高边墙洞室开挖卸荷三维地质力学模型试验,揭示高边墙洞室开挖卸荷的非线性变形特征与劈裂破坏规律。在地质力学模型试验研究的基础上,建立基于应变梯度的地下洞室劈裂破坏弹塑性损伤软化模型和岩体劈裂破坏准则,并据此依托ABAQUS软件开发地下洞室劈裂破坏计算分析程序,通过多工况数值模拟分析,有效揭示高边墙洞室劈裂破坏的产生条件和形成力学机制。研究表明:洞区初始最大主应力平行于洞轴向且其量值达到一定程度是产生劈裂破坏的重要条件;开挖卸荷过程中高边墙洞壁应力出现波峰与波谷间隔交替的振荡变化是引起劈裂破坏的根本力学成因,该研究成果为下一步进行高边墙洞室劈裂破坏防治提供了重要试验和理论依据。The splitting failure of high sidewall caverns has become an important factor affecting the construction and excavation safety of the underground powerhouse of large hydropower stations.In order to clarify the formation mechanism of this phenomenon,taking the high sidewall cavern of the main powerhouse of Pubugou Hydropower Station as a case study,the true 3D geomechanical model test of excavation and unloading of high sidewall cavern under high in-suit stress is carried out,and the nonlinear deformation characteristics and splitting failure law of excavation and unloading of high sidewall cavern are revealed.On the basis of the model test,an elastic-plastic damage-softening model of splitting failure of underground cavern based on strain gradient and the failure criterion of splitting failure are established.Based on this,the calculation and analysis program of underground cavern splitting failure is developed based on ABAQUS software.Through the numerical simulation of multiple working conditions,the generation conditions and formation mechanism of splitting failure of high sidewall cavern are effectively revealed:the important condition of splitting failure is that the initial maximum principal stress is parallel to the direction of tunnel axis and the value reaches a certain degree.In the process of excavation and unloading,the oscillating change of the stress of the high sidewall is the fundamental mechanical cause of splitting failure.The research results provide an important experimental and theoretical basis for the prevention and control of splitting failure of high sidewall caverns.

关 键 词：岩石力学 高边墙洞室劈裂破坏 地质力学模型试验 应变梯度 劈裂破坏弹塑性损伤软化模型 劈裂破坏数值模拟 

分 类 号：TU45[建筑科学—岩土工程]