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界面形态对黄土-泥岩接触面剪切力学特性影响研究

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黄土-泥岩接触面滑坡具有"双层异质"、较隐蔽、复活性强的特点,但现阶段研究主要针对该类滑坡的诱发因素及破坏机理,对黄土-泥岩接触面的剪切力学特性,特别是接触面形态对剪切力学特性影响的研究尚浅.因此本文通过不同工况下的黄土-泥岩接触面直剪试验和基于颗粒流软件PFC2D的数值模拟,研究了不同黄土-泥岩接触面形态对其抗剪强度的影响及作用机理.结果表明:(1)界面形态对抗剪强度的影响主要体现在界面起伏表面积和剪切影响厚度对界面粗糙度的影响上,在相同法向压力下,界面粗糙度越大,接触面抗剪强度越高;(2)黄土-泥岩接触面试样的剪切破坏模式可分为沿界面滑动、界面滑动-凸体剪断和凸体直接剪断破坏3类,其演化受法向压力和凸体起伏角的影响;(3)随着界面粗糙度的增大,黄土与泥岩间的有效接触面积增大,界面处的颗粒嵌入量增大,界面抗剪强度显著提高.结果可为黄土-泥岩接触面滑坡的预警与防治提供一定的理论支撑.
EXPERIMENTAL STUDY ON SHEAR STRENGTH OF CONTACT SURFACE BETWEEN LOESS AND MUDSTONE
The loess-mudstone interface landslide,as a kind of loess landslide,has the characteristics of double-layer heterogeneity,short slip distance and strong reactivity.Due to the low rate of deformation before the occur-rence of landslides,it is often difficult to detect early,and it has caused serious damage when discovered.Research on the inducing factors and failure mechanisms of this type of landslide have been abundant.However,there are few studies on the loess-mudstone interface,especially the shear mechanical properties of the interface,and the influ-ence mechanism of each factor on the shear strength of the interface is still unknown.Therefore,in order to investi-gate the influences of water content,dry density,and interface morphology on shear strength,cohesion,and inter-nal friction of loess-mudstone interface samples,a series of shearing experiments were performed using a direct shear apparatus.The results show that as the moisture content of the loess increases,the shear strength of the inter-face first decreases slightly,and then decreases rapidly when the moisture content of the upper loess exceeds that of the lower mudstone.As the dry density of loess increases,the shear strength of the interface increases,but com-pared with the water content,dry density has a smaller effect on the interface shear strength.The influence of inter-face morphology on the shear strength is mainly reflected in the influence of the surface area of the undulating sur-face and the thickness of the shearing influence on the interface roughness.The deeply zigzagged interface has the highest shear strength and the smooth interface has the lowest under the same normal stress.

Loess-mudstone contact surfaceShear strengthSurface morphologyNumerical simulationMicro-structure

许博闻、兰恒星、刘世杰

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长安大学地质工程与测绘学院,西安 710054,中国

中国科学院地理科学与资源研究所,资源与环境信息系统国家重点实验室,北京 100101,中国

生态地质与灾害防控自然资源部重点实验室,西安 710054,中国

黄土-泥岩接触面 抗剪强度 界面形态 数值模拟 微结构

国家自然科学基金项目国家自然科学基金项目国家自然科学基金项目

420410064192780641790443

2024

工程地质学报
中国科学院地质与地球物理研究所

工程地质学报

CSTPCD北大核心
影响因子:1.215
ISSN:1004-9665
年,卷(期):2024.32(2)
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