Buckling Failure Mechanism of a Rock Dam Foundation Fractured by Gentle Through-Going and Steep Structural Discontinuities

Donghui Chen,Wen Zhang,Huie Chen,Chun Tan,Bo Shan,Zhifa Ma,Jianye Chen

doi:10.3390/su12135426

Abstract

The failure mechanism analysis of dam foundations is key for designing hydropower stations. This study analyses the rock masses in a sluice section, which is an important part of the main dam of the Datengxia Hydropower Station currently built in China. The stability of the sluice rock masses is predominantly affected by gentle through-going soft interlayers and steep structural fractures. Its foundation failure mechanism is investigated by means of a numerical method, i.e., Universal Distinct Element Code (UDEC) and the geomechanical model method. The modeling principle and process, and results for the rock dam foundation are introduced and generated by using the abovementioned two methods. The results indicate that the failure mechanism of the foundation rock masses, as characterized by gentle through-going and steep structural discontinuities, is not a conventional type of shear failure mechanism but a buckling one. This type of failure mechanism is verified by analyzing the deformation features resulting from the overloading of both methods and strength reduction of the numerical method.

Highlights

To satisfy the enormous energy demands, many high gravity dams are being or will be built in China [1,2]
It is plausible that the rock masses of the sluice are not predominantly affected by shear displacement but are subjected to compression forces leading to intact rock deformation
This study takes the Datengxia Hydropower Station, which is a primary project of the Chinese Ministry of Water Resources for 2016–2020, as a research object

Summary

Introduction

To satisfy the enormous energy demands, many high gravity dams are being or will be built in China [1,2]. Three approaches are commonly executed for the mechanical and deformation analyses of dam foundations: the limit equilibrium method, geomechanical model method and numerical method [5,6]. The advantages of using the numerical method lie in its flexibility to model complex geometries and geologic conditions, and its ability to simulate a variety of material behaviors and incorporate the influence of construction procedures. The advantages of both the geomechanical model method and numerical method can be synthesized for effective utilization. Complex engineering technical problems can be comprehensively analyzed and verified from different perspectives

Objectives

Discussion

Conclusion