基于大型叠环剪切试验的松散土石体强度及变形特性试验研究

发布时间：2018-01-07 10:40

本文关键词：基于大型叠环剪切试验的松散土石体强度及变形特性试验研究　出处：《岩石力学与工程学报》2017年S1期 　论文类型：期刊论文

【摘要】：松散土石体广泛存在于自然界及实际工程中。以强风化板岩松散碎石料为研究对象,在对松散土石体制样方法成功尝试后,采用大型叠环式剪切试验机对不同相对密度(D_r)及不同干湿状态的松散土石体开展系统力学试验,得到以下主要结论:松散土石体颗粒组构间约束效应及机械咬合弱,其应力应变曲线无显著峰值,大变形过程主要呈现为颗粒间的滑动摩擦与翻转;对于试验中所选取的3种D_r(0.30,0.35和0.40),干燥状态下松散土石体内摩擦角由D_r=0.30时的13.18°小幅升至D_r=0.40时的13.97°,黏聚力则由6.95 kPa略降至4.90 kPa,湿润和浸水状态下亦呈现此规律,表明相同干湿状态时该松散度区间内土石体强度基本保持稳定;干燥状态松散土石体剪应力峰值显著高于湿润及浸水状态,表现出显著的水敏感性;以D_r=0.40为例,经与常规三轴试验成果对比,凸显了采用叠环式剪切试验研究松散土石体工程特性的优势与适用性。研究初步揭示了松散状态土石体强度及变形特性,其显著的水敏感性可定量解释松散堆积体、松散滑坡等受水的影响而发生大变形或失稳的机制。
[Abstract]:Loose soil and rock bodies widely exist in nature and practical engineering. Taking loose gravel of strongly weathered slate as the research object, the method of loose soil and rock system has been successfully tried. Systematic mechanical tests were carried out on loose soil and rock with different relative densities and different dry and wet states by using a large annular shear tester. The main conclusions are as follows: the intergranular confinement effect and mechanical bite of loose soil and rock body are weak, the stress and strain curves have no significant peak value, and the large deformation process mainly presents sliding friction and turnover between particles; For the three types of DSPs selected in the experiment, they are 0.300.35 and 0.40). Under dry condition, the friction angle of loose soil and rock increased slightly from 13.18 掳at 0.30 to 13.97 掳at 0.40. The cohesive force decreased slightly from 6.95 kPa to 4.90 KPA, and it also showed this rule under wet and wet conditions, indicating that the strength of soil and rock remained stable in the same dry and wet state. The peak shear stress of loose soil and rock in dry state is significantly higher than that in wetting and soaking state, showing significant water sensitivity. Taking DRC 0.40 as an example, the results were compared with the results of conventional triaxial test. The advantages and applicability of using overlapping shear test to study the engineering characteristics of loose soil and rock body are highlighted. The strength and deformation characteristics of loose soil and rock body are revealed preliminarily. Its remarkable water sensitivity can quantitatively explain the mechanism of large deformation or instability caused by the influence of water on loose accumulations, loose landslides and so on.
【作者单位】：长江科学院水利部岩土力学与工程重点实验室;
【基金】：国家自然科学基金资助项目(51409011) 中央级公益性科研院所基本科研业务费项目(CKSF2015051/YT)~~
【分类号】：TU43
【正文快照】： 松散土石体广泛存在于自然界及实际工程中,诸如自然界的滑坡堆积体、泥石流堆积体等。其最大特点是宽级配、弱固结,受包括水的作用等外界因素影响后,极易产生大变形或失稳破坏,对其强度及变形特性进行研究很有必要。国外学者对土石体的研究起步相对较早,E.Medley[1-2]最早基于

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