摘要
上、下盘抗压强度不一致的软-硬节理的抗剪强度难以准确获取,应用Barton模型等常用的岩石节理抗剪强度模型也不能准确表征这类特殊节理的抗剪强度。借助三维激光扫描和3D打印技术,浇筑了具有自然节理形貌上下盘抗压强度相同以及上下盘抗压强度不同的人工节理试样,并对其进行常法向应力下的剪切试验。分析了法向应力、三维形貌特征以及节理强度比对软-硬节理的抗剪强度和剪胀角的影响。试验结果表明:节理抗剪强度与法向应力、节理强度比和节理粗糙度呈正相关;剪胀角与法向应力呈负相关,与节理强度比和节理粗糙度呈正相关。通过研究剪胀角在剪切过程中随法向应力和节理强度比的演化规律,建立了含有三维形貌参数和节理强度比的岩石节理抗剪强度模型。通过与Barton模型的对比分析,验证了所提出模型的可靠性。采用该文模型计算云南某水电站库区内不稳定斜坡平硐内出现的软-硬节理的抗剪强度,计算结果和试验值较为接近,论证了该模型的适用性。
It is difficult to accurately obtain the shear strength of soft-hard joints of hanging walls and footwalls with different compressive strengths.The shear strength of such special joints cannot be accurately characterized by the commonly used rock joint shear strength models such as the Barton models.We used three-dimensional laser scanning and three-dimensional printing technology to pour artificial joint samples that have the natural joint morphology and the same or different compressive strengths of the hanging walls and footwalls.Shear tests under normal stress were carried out on the samples to analyze the effects of normal stress,three-dimensional morphology and joint strength ratio on the shear strength and dilatancy angle of soft-hard joints.The test results revealed that the shear strength of the joints was positively correlated with the normal stress,joint strength ratio and joint roughness,and that the dilatancy angle was inversely correlated with the normal stress,and positively correlated with the joint strength ratio and joint roughness.By studying the evolution law of the dilatancy angle with the normal stress and the joint strength ratio in the shear process,we established a shear strength model of rock joint with three-dimensional morphology parameters and the joint strength ratio.The reliability of the proposed model was verified by comparison with the Barton model.The model was used to calculate the shear strength of the soft-hard joints in the adit of the unstable slope in the reservoir area of a hydropower station in Yunnan Province.The calculation results were similar to the test values,which proved the applicability of the model.
作者
金磊磊
魏玉峰
JIN Lei-lei;WEI Yu-feng(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology),Chengdu,Sichuan 610059,China)
出处
《工程力学》
EI
CSCD
北大核心
2020年第12期180-190,共11页
Engineering Mechanics
基金
国家重点研发计划项目(2017YFC1501000)
国家自然科学基金项目(42072303)。
