张亦凡, 伍纯昊, 李渝生, 等. 2024. 同震岩体损伤特征的定量分析——以2022年泸定MS6.8地震为例[J]. 工程地质学报, 32(3): 1020-1034. doi: 10.13544/j.cnki.jeg.2023-0216.
    引用本文: 张亦凡, 伍纯昊, 李渝生, 等. 2024. 同震岩体损伤特征的定量分析——以2022年泸定MS6.8地震为例[J]. 工程地质学报, 32(3): 1020-1034. doi: 10.13544/j.cnki.jeg.2023-0216.
    Zhang Yifan, Wu Chunhao, Li Yusheng, et al. 2024. Quantitative analysis of damage characteristics of coseismic rock mass: A case of 2022 MS6.8 Luding earthquake[J]. Journal of Engineering Geology, 32(3): 1020-1034. doi: 10.13544/j.cnki.jeg.2023-0216.
    Citation: Zhang Yifan, Wu Chunhao, Li Yusheng, et al. 2024. Quantitative analysis of damage characteristics of coseismic rock mass: A case of 2022 MS6.8 Luding earthquake[J]. Journal of Engineering Geology, 32(3): 1020-1034. doi: 10.13544/j.cnki.jeg.2023-0216.

    同震岩体损伤特征的定量分析——以2022年泸定MS6.8地震为例

    QUANTITATIVE ANALYSIS OF DAMAGE CHARACTERISTICS OF COSEISMIC ROCK MASS: A CASE OF 2022 MS6.8 LUDING EARTHQUAKE

    • 摘要: 强烈地震动会对地壳浅表层岩体产生震裂损伤,导致岩体完整性与稳定性降低,继而诱发次生地质灾害。由于地震不可预知性与岩体复杂性等诸多限制存在,致使同震岩体损伤研究的定量化程度不足,尤其缺乏地震发生前后野外现场岩体损伤特征的直观对比。本文以2022年泸定MS6.8地震为例,对发震前后相同位置岩体损伤变化开展定性与定量分析,取得如下认识:(1)地表岩体在地震动荷载作用下会出现物理和力学性质改变,根据损伤类型与规模等差异可将泸定地震岩体损伤区划分为高、低损伤区,低损伤区内损伤形式包括先期裂隙轻度张裂、裂隙端部扩展、临空块裂岩体塌落,高损伤区表现为损伤裂隙强烈张开与新生、宏观破裂。(2)岩体震裂损伤程度在发震断裂附近达到极值,较震前结构面长度密度平均增加3.44%,结构面数量密度平均增大6.46%,且存在断层距离效应。并采用误差因素削减的方法对调查损伤程度进行了修正。(3)选取岩性、震中距、地质强度指数(GSI)、地震峰值加速度(PGA)等8个指标,采用层次分析法建立了同震岩体损伤评价模型,评价损伤程度与修正后调查损伤程度间平均误差为12.5%。本研究可望为深入理解地壳岩体动力响应和地震次生灾害形成规律提供新的科学证据。

       

      Abstract: Strong earthquakes can cause fractures and damage to rock masses, leading to the occurrence of geological hazards. Earthquakes, being unpredictable, coupled with the inherent discontinuity and complexity of rock masses, result in insufficient quantitative studies on coseismic rock mass damage. Particularly, there is a lack of comparison of actual damage characteristics before and after earthquakes. Therefore, this article takes the Luding MS6.8 earthquake in 2022 as an example and conducts qualitative and quantitative research on its damage to rock masses. The adopted methods and main findings are as follows: (1)According to differences in the type and grade of damage, the research area is separated into high and low damage zones. The forms of damage manifest as macroscopic ruptures and fissures strongly opened or regenerated in the high damage zone, while collapses and tension cracks in the rear of the rock mass are discovered in the low damage zone. (2)The degree of rock mass damage can reach an extreme value near the seismogenic fault. The linear density of structural planes increased by 3.44% relative to pre-earthquake levels, and the numerical density of structural planes increased by an average of 6.46%. Additionally, this research introduced an indicator to correct the surveyed damage degree. (3)By using the analytic hierarchy process method, this research established a coseismic rock mass damage evaluation and prediction model. The model considered eight influencing factors, including lithology, epicentral distance, Geological Strength Index(GSI), slope structure, distance from fault, shear wave velocity(VS30), peak ground acceleration(PGA), and peak seismic velocity(PGV). The results show that the assessment is similar to the actual coseismic damage degree. Hence, this study can provide new scientific evidence for understanding the formation mechanism of seismic secondary disasters.

       

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