摘要
中国西南地区溶蚀岩体分布广泛。岩溶作用下,结构面强度持续劣化是影响岩体稳定性的重要因素之一。为探究溶蚀作用下结构面的演化特征,揭示岩溶作用对灰岩结构面剪切力学特性的影响,以武隆鸡尾山溶蚀岩质坡体为例,采用室内结构面渗流溶蚀试验和结构面直接剪切试验,并结合三维形貌光学扫描技术,阐明了水动力-溶蚀作用灰岩结构面的表观演化模式和剪切力学特性演化规律,揭示了水动力-溶蚀作用下结构面劣化机理。结果表明:灰岩结构面在化学溶蚀和物理冲蚀双重作用下,先后经历“点式选择性溶蚀—细槽线式稳定渗流溶蚀—优势管道流强烈溶蚀—壁面缓慢溶蚀”4个阶段;溶蚀过程中,灰岩结构面表面粗糙度指数和溶蚀率指标随时长增大而增大,并呈收敛趋势;直剪过程中,溶蚀结构面表现出初期锁固、后期剪摩阻滑的两阶段特征,且时间越长、应力水平越高,剪切硬化特征越显著;随溶蚀时间增长,结构面主要抗滑结构由刚性稳定微凸体发展为细微溶槽并最终演变为深大岩溶管道,其极限抗剪强度呈现出“先减小,后增大”的趋势;基于Barton公式建立了灰岩溶蚀结构面抗剪强度预测模型。
The dissolved rock mass is widely distributed in Southwest China.Under the action of karst,the continuous deterioration of structural plane strength is one of the important factors affecting the stability of rock mass.In order to explore the evolution characteristics of structural plane under dissolution and to reveal the influences of karstification on the shear mechanical properties of limestone structural plane,based on the example of the dissolution rock slope of Jiwei Mountain in Wulong,the apparent evolution patterns of limestone structural plane and the evolution laws of shear mechanical properties as well as the deterioration mechanism of structural plane are expounded by using the indoor seepage dissolution and direct shear tests on the structural plane and the three-dimensional morphology optical scanning technology.The results show that under the dual action of chemical corrosion and physical erosion,the limestone structural plane has experienced four stages:point selective dissolution,thin groove linear stable seepage dissolution,strong dissolution of dominant pipeline flow and wall slow dissolution.During the dissolution process,the surface roughness index and dissolution rate index of limestone structural plane increase with the increase of dissolution time,and exhibit a convergence trend.During the direct shear process,the corrosion structural plane shows two-stage characteristics of the initial locking and the later shear friction and sliding,and the longer the corrosion time and the higher the stress level,the more obvious the shear hardening characteristics.With the increase of the corrosion time,the main anti-sliding structure of the structural plane develops from a rigid stable microconvex to a fine solution groove and finally evolves into a deep karst pipeline,and its ultimate shear strength shows a trend of“first decreasing,then increasing”.The prediction model for shear strength of limestone dissolution structural plane is established based on the Barton's formula.
作者
杨忠平
向宫固
赵茜
刘新荣
赵亚龙
YANG Zhongping;XIANG Gonggu;ZHAO Qian;LIU Xinrong;ZHAO Yalong(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area(Chongqing University),Ministry of Education,Chongqing 400045,China;National Local Joint Engineering Research Center for Prevention and Control of Environmental Geological Disasters in Reservoir Area(Chongqing),Chongqing 400045,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2023年第8期1555-1563,共9页
Chinese Journal of Geotechnical Engineering
基金
国家重点研发计划课题(2021YFB3901402,2018YFC1504802)
国家自然科学基金项目(41972266)。
关键词
岩溶
结构面
剪切特性
强度预测模型
粗糙度
鸡尾山
karst
structural plane
shear characteristic
strength prediction model
roughness
Jiwei Mountain
作者简介
杨忠平(1981—),男,教授,博士生导师,主要从事环境岩土与边坡稳定性方面的教学与研究工作。E-mail:yang-zhp@163.com。
