Title of Paper:基于微震监测与数值模拟的大岗山右岸边坡抗剪洞加固效果分析

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Date of Publication:2022-10-10

Journal:岩石力学与工程学报

Affiliation of Author(s):建设工程学部

Issue:6

Page Number:1239-1247

ISSN No.:1000-6915

Abstract:The right bank slope of Dagangshan hydropower station is steep and high, characterized by high in-situ stress. The geological defects in this project include diabase dikes, dense belts of unloading fissures and faults moderately dipping outside slope, which attribute to the poor rock mass quality. In addition, several sets of macrocracks were observed during excavation, which greatly threatened the slope stability unexpectedly. In this paper, the microseismic monitoring technology is employed in combination of numerical simulations, i.e. the software RFPA3D. The RFPA3D can consider the constitutive relationship of quasi-brittle materials such as rocks. Consequently, slope stabilities with and without anti-shear gallery are conducted. Also, the potential sliding surface of slope failure is determined by microseismic events of rock mass spatial damages during slope excavation. The results confirm the rationality of anti-shear gallery. It is found that the shear resistance against sliding of the structured rock mass increases significantly after concrete replacement in anti-shear gallery. The monthly microseismic events were reduced by 66.4% after application of anti-shear gallery, and the factor of safety of slope increases by 51.2%. However, owing to the complex slope structures, the possibility of local instability still exists in the process of slope excavation. Therefore, it is suggested to lockup shearing outlet in the construction progress, and to monitor the microfracturing of rock mass where the anti-shear gallery did not pass through. The rock deformation at the junction between the unloading fissure XL-316 and fault f231 should be observed in the later stage when pouring concrete is performed on the dam.

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