摘要
深切峡谷中电站库区岩质边坡开挖过程中形成的卸荷岩体,是影响边坡开挖支护设计与防范库岸产生渗透潜蚀作用及实现坡体长期变形预测所需关注的重点对象。以某电站库区岩质开挖边坡为对象,结合工程地质剖面及应力卸荷量,构建了考虑分级开挖过程和开挖面附近岩体卸荷松弛效应的数值计算模型;以室内分级卸荷试验为基础,界定了不同卸荷量级下变形参数的取值范围;综合对比岸坡初始场应力应变试算结果,遴选确定了考虑开挖卸荷效应的岩体力学参数;结合本构模型的优缺点,对比了Mohr-Coulomb与Drucker-Prager准则分析开挖卸荷岩体的适用性。结果表明:对象边坡初始场特征是遴选岩体计算参数的基础,卸荷分带的预估可为边坡开挖支护范围及变形预测提供参考,区分边坡拉剪与压剪等应力状态是本构模型优选的前提。
The unloading rock mass formed during the excavation of the rock slope in the reservoir area of the power station in the deep canyon is the key object that affects the design of slope excavation and support,prevents the seepage potential corrosion of the reservoir bank and realizes the long-term deformation prediction of the slope.Taking the rock excavation slope in the reservoir area of a power station as the study object,combined with the engineering geological profile and stress unloading,a numerical calculation model considering the graded excavation process and the unloading relaxation effect of rock mass near the excavation surface is constructed.Based on the indoor step-by-step unloading test,the value range of deformation parameters under different unloading orders is defined;By comprehensively comparing the trial results of stress and strain in the initial field of bank slope,the mechanical parameters of rock mass considering excavation unloading effect are selected and determined;Combined with the advantages and disadvantages of the constitutive model,the applicability of Mohr-Coulomb criterion and Drucker-Prager criterion for analyzing excavated unloaded rock mass is compared.The results show that the initial field characteristics of the object slope are the basis for selecting the calculation parameters of rock mass.The prediction of unloading zoning can provide a reference for the excavation and support range and deformation prediction of slope.Distinguishing the stress states such as tension shear and compression shear of slope is the premise for the optimization of constitutive model.
作者
白亚妮
胡习文
毛振凯
袁秋霜
陈兴周
BAI Yani;HU Xiwen;MAO Zhenkai;YUAN Qiushuang;CHEN Xingzhou(Department of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,China;China Gezhouba Group Co.,Ltd.Wuhan 430000,China;PowerChina Northwest Engineering Corporation Limited,Xi'an 710065,China)
出处
《西北水电》
2022年第6期104-110,共7页
Northwest Hydropower
基金
国家自然科学基金项目(U1965107,51979218)
陕西省自然科学基金项目(2018JM5118)。
关键词
水工边坡
开挖卸荷
数值计算
强度准则
变形分析
hydraulic slope
excavation unloading
numerical calculation
strength criterion
deformation analysis