陡倾顺层斜坡动力响应及失稳机理的离心振动台模型试验研究

发布时间：2018-03-24 05:02

本文选题：陡倾顺层斜坡　切入点：离心机振动台　出处：《成都理工大学》2017年硕士论文

【摘要】：我国地处环太平洋地震带和地中海-喜马拉雅地震带之间,是全世界最大的大陆地震区,也是一个地震频发的国家。在斜坡高陡的西部山区,地震会促使高陡斜坡失稳,诱发崩塌、滑坡、泥石流等次生地质灾害。2008年5月12日,汶川大地震就诱发了不计其数的崩塌、滑坡等地质灾害,对震中区及其周边地区造成了灾难性的破坏。在对汶川大地震诱发的次生地质灾害的调查中,发现了大量的陡倾顺层斜坡整体失稳的现象,这和传统“陡倾斜坡稳定性较好”的认识不一致。这类斜坡在强震作用下是怎么失稳的,只有研究强震作用下陡倾顺层斜坡的失稳机理以及动力响应规律才能阐明这一问题。本文以“5.12”汶川地震为研究背景,通过对汶川地震区大量陡倾顺层斜坡失稳特征,现场调查分析的基础上,建立概念模型,结合离心振动试验方法,分析探讨陡倾顺层斜坡的动力响应特征及失稳机理,其主要工作与成果如下:(1)根据现场调研汶川地震诱发的大量陡倾顺层边坡动力失稳实例为基础,选取其中典型的干磨房滑坡和大竹坪崩滑为例,抽象概化出层状硬岩和软硬互层两种不同坡体结构的陡倾顺层斜坡。(2)根据动力离心模型试验的基本原理以及相似量纲分析原理确定了模型试验的相似常数,开展了模型斜坡硬岩和软岩的选材和配比试验,通过比较遴选出模型试验的最优相似材料和相应的配合比,并按照试验所需选取了相应的测量元器件并对试验测点布置进行设计,按照试验目的确定了地震波的加载方案。通过对整个试验的设计与实施,建立了适用于陡倾顺层斜坡动力离心模型试验的一套比较优化的试验方法。(3)采用土工离心机开展了陡倾顺层斜坡的离心振动台模型试验,通过高速摄像机和监视系统观察两个斜坡模型的变形破坏特征,然后分析斜坡变形破坏的演化过程,进而分析陡倾顺层斜坡的失稳机理。分析表明,陡倾层状硬岩斜坡以崩塌和坡肩岩体抛射为主,而软硬互层斜坡的破坏方式主要为滑移-弯曲。(4)对比分析了层状硬岩斜坡和软硬互层斜坡在不同地震加载情况下监测的加速度数据,探讨了地震动参数和斜坡体自身地质条件对陡倾顺层斜坡地震动力响应的影响规律。综合考虑了对斜坡地震动力响应造成影响各种因素,分析得出了陡倾顺层斜坡的水平放大效应、高程放大效应、临空面效应、不同振幅条件下斜坡的动力响应规律以及不同坡体结构斜坡的动力响应规律。动力响应分析结果很好的揭示了陡倾顺层斜坡在地震作用下的变形破坏特征及失稳机理。(5)通过三维离散元软件3DEC反演了陡倾顺层斜坡的破坏形式,在此基础上分析了层状硬岩和软硬互层斜坡在地震荷载作用下边坡的破坏模式,并与离心振动台模型试验的结果相对比。结果表明数值模拟计算与离心振动台模型试验的斜坡破坏特征是基本吻合的,由此可见,数值模拟基本反映了陡倾顺层斜坡离心振动台模型试验中坡体的整个破坏过程。
[Abstract]:Our country is located in the circum Pacific seismic belt and Mediterranean - Himalaya earthquake belt, is the world's largest region, earthquake, is an earthquake prone country. In high and steep slope of the mountain west, the earthquake will lead to high and steep slope instability, induced collapse, landslide, debris flow and other secondary geological disasters in.2008 May 12th Wenchuan earthquake caused the collapse of too many to count, landslides and other geological disasters, causing catastrophic damage to the epicenter and its surrounding areas. In the investigation of secondary geological disasters induced by the Wenchuan earthquake, found a large number of steep bedding slope overall instability phenomenon, and the traditional "steep slope stability better" is not consistent. This is how the slope instability under strong earthquake, only study earthquakes steep bedding slope instability mechanism and dynamic response law in order to clarify this issue. Based on the "5.12 Wenchuan earthquake" as the research background, through to the Wenchuan earthquake region of steep bedding slope instability characteristics, based on the field investigation and analysis, a conceptual model is established. Combined with the test method of centrifugal vibration analysis of steep bedding slope dynamic response characteristics and failure mechanism, the main work and results are as follows: (1) according to a large number of field investigation of Wenchuan earthquake induced by steep inclined bedding slope dynamic instability as an example, the typical dry mill landslide and Dazhu Ping landslide as an example, the abstract generalized layered hard rock and soft and hard interbedded with two different slope structures (steep bedding slope. 2) according to the basic principle of dynamic centrifuge model test and similar dimension analysis principle to determine the similarity constants of model test, carried out the material and ratio of the test model of hard rock and soft rock slope, by comparing the selection of optimal model test Similar materials and the corresponding proportion, and in accordance with the test required for selected components corresponding measurement and design on the arrangement of testing points, according to the test to determine the seismic wave loading scheme. Through the design and implementation of the test, is established on a steep optimization test method of bedding slope dynamic centrifuge model test. (3) carried out by centrifuge centrifuge shaking table model test of steep bedding slope, with high-speed camera and monitor system observation two slope deformation characteristics of the model, and then analyzes the evolution process of slope deformation and failure, and then analyzes the instability mechanism of steep bedding slope. Analysis shows that the steep layered slope with hard rock collapse and rock slope shoulder projectile, and the failure mode of soft and hard interbedded slope mainly slip - bending. (4) comparison and analysis of the hard rock and soft layered slope The acceleration data of interbedded slope in different seismic loading monitoring, discusses the ground motion parameters and its slope geological conditions on steep slope along the influence of layer seismic response. Considering the impact of various factors on the seismic response analysis of the slope, steep bedding slope level amplification effect. Elevation amplification effect, surface effect, dynamic responses of the dynamic response of different amplitudes and different slope slope slope structure. The dynamic response analysis of good results revealed a steep slope in the layer along the deformation characteristics under earthquake and the instability mechanism. (5) by three-dimensional discrete element software 3DEC the failure form of inversion of steep bedding slope, based on the analysis of the failure modes of layered hard rock and soft and hard interbedded slope slope under seismic load, and the centrifugal vibration table The results of the model test are compared. The results show that the numerical simulation is basically consistent with the slope failure characteristics of the centrifugal shaking table model test. Therefore, the numerical simulation basically reflects the whole failure process of the slope in the centrifuge shaking table model test of steep slope.

【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU43

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