Geological Structure and Rock Deformation Characteristics and Their Geohazard-Controlling Mechanism in Yajiang Area, West Sichuan

doi:10.19657/j.geoscience.1000-8527.2021.007

Abstract

Abstract:

Structural patterns of compound anticlines and synclines with faults superimposed are widely developed in Yajiang area, west Sichuan. Due to intensive tectonic reworking, at least seven rock deformation types present in the study area, including flexible slippage, bedding shear, brittle bending, unloading along structural planes, large-scale dislocation, fault fracture and fold cleavage. Structural-lithologic assemblage has shaped the distribution of Yalong river and valley evolution. Meanwhile, the development and distribution of geohazards, e.g., landslides and collapses, and their stability and risk are controlled by valley evolution and tectonic reworking. The different of geohazard types are controlled by various rock deformation types, and the lithologic association has constrained their size. Interbedded sand-slate controlled by brittle bending has often experienced toppling-drawing breakage-slippage-unstable failure-river blockage, and the multistage slope evolution represents the main geohazard model in Yajiang area.

Key words: Yajiang area, geological structure, rock deformation, geohazard distribution, geohazard-controlling mechanism

CLC Number:

P642

XIONG Xiaohui, BAI Yongjian, TIE Yongbo. Geological Structure and Rock Deformation Characteristics and Their Geohazard-Controlling Mechanism in Yajiang Area, West Sichuan[J]. Geoscience, 2021, 35(01): 145-152.

Figures/Tables 6

Fig.1 Geological environmental conditions and geohazard distribution in the study area

Fig.2 Structural stratigraphic profile across Yajiang County Town and Xidi Village

Fig.3 Rock deformation patterns in the study area

Table 1 Development and distribution statistics of geohazards in the study area

分布区域		滑坡/个	崩塌/个	泥石流/个
与断裂的距离/km	<2	32	3	13
	2~4	32	10	15
	4~6	27	6	14
	>6	45	10	34
总计		136	29	76
与雅砻江干流的距离/km	<1	63	16	17
	1~2	21	0	4
	2~3	8	2	4
	>3	44	11	51
总计		136	29	76

Fig.4 Structural and geomorphic features and typical landslides in the study area

Fig.5 Geological model of Jiaxi landslide and schematic diagram of rock deformation

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