In-situ rock tests for fault gouge zone：A case in Fengman hydropower station, China

Ximeng Xu ,Xiaogang Long,Changyan Ke,Zhaoyue Yu,Huanyu Meng,Yuefei Wang,Xinyu Mao,Fangzheng Xue

doi:10.1051/e3sconf/202129303008

Abstract

The existence of faults in the dam site area threatens the stability and safety of large-scale hydropower projects in China. The fault argillaceous zone is the worst kind of fault fracture zone, and the determination of its deformation and strength parameters is the key point of rock engineering investigation. In this study, the in-situ bearing plate test and direct shear test were carried out on the gouge zone of F67 fault in the dam site of Fengman Hydropower Station. The test results show that the deformation and shear law of each test point is good, which is basically consistent with the actual condition of the measured rock mass. However, due to the limited number of measurements, the results are limited in terms of macroscopic representation. The experimental results provide scientific basis for subsequent engineering design and further enhance the understanding of mechanical properties of fault gouges.

Highlights

With the rapid development of China’s economy, the pace of various types of energy and infrastructure construction is accelerating
From the perspective of engineering geology, the fault argillaceous zone is a kind of weak zone compared with surrounding rock, and it is the boundary condition for many geological disasters
In terms of the physical and mechanical research of fault gouges, Geng et al conducted systematic experimental studies on the mechanical properties of fault gouge in Honghe fault, Yimu fault, Haiyuan fault, Fuyun fault and Xianshuihe-Xiaojiang fault, which made scholars have a preliminary understanding of the mechanical properties of fault gouge in China [10]

Summary

Introduction

With the rapid development of China’s economy, the pace of various types of energy and infrastructure construction is accelerating. From the perspective of rock mechanics, the fault argillaceous zone is the key research object of rock engineering due to its poor mechanical properties, low strength and wide distribution [4]. In the long-term engineering practice, the physical and mechanical properties of rock mass in fault zone have been extensively studied, and abundant test data have been accumulated. Many scholars have studied the physical and mechanical properties of fault fracture zones in depth [5,6,7,8,9]. Han made a detailed study and analysis of the physical and mechanical parameters of fault gouges at the Daliushu dam site of the Black Three Gorges, and connected it with its formative environment, which provided a reliable basis for demonstrating the quality of loose rock mass in the Black Three Gorges [11]. Klima conducted shear tests on clay-rich fault gouge samples and established a probabilistic prediction model for the shear strength performance [12]

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Discussion

Conclusion