软弱夹层的极限荷载分析

发布时间：2018-03-22 01:29

本文选题：软弱夹层　切入点：塑性极限平衡　出处：《岩土力学》2015年04期 　论文类型：期刊论文

【摘要】：岩土体中的软弱夹层是一种广泛存在的地质体,由于其力学性质较差,容易给工程建设带来安全隐患,对其稳定性的研究逐步引起重视。根据塑性极限平衡分析方法,针对软弱夹层的承载稳定问题,将软弱夹层上下土层当作准刚性层,基于修正Prandtl挤压理论解答对软弱夹层的极限荷载进行了计算。分析过程中认为,准刚性层间的软弱夹层在极限状态下发生塑性挤出破坏,考虑到Prandtl挤压理论的剪应力解答在x方向上的不足,结合不同的边界应力条件,对软弱夹层中的应力分量和夹层表面的极限荷载进行了重新求解。推导的极限荷载实用计算式能综合考虑软弱夹层面的摩擦条件、土层自重及夹层周围的受力状态等因素,并与其他理论计算式的结果进行了对比分析。计算结果分析表明,不考虑土重时,该方法计算的夹层极限荷载随厚度变化规律与Prandtl方法基本一致;考虑土重影响时,该方法计算结果与规范法相似,但在夹层较厚时能更明确地反映宽度对极限荷载的影响。此外,夹层上下边界的摩擦条件对极限荷载的影响程度随夹层宽厚比的不同而变化,对于一定厚度的夹层存在几乎不受摩擦条件影响的临界宽度。其研究结果可为软弱夹层的承载稳定分析提供参考。
[Abstract]:The weak intercalation in rock and soil is a kind of widely existing geological body. Because of its poor mechanical properties, it is easy to bring safety hidden trouble to engineering construction, so the study of its stability has been paid more and more attention. According to the plastic limit equilibrium analysis method, In view of the problem of bearing stability of weak intercalation, the upper and lower layers of soft intercalation are regarded as quasi rigid layers, and the ultimate load of soft intercalation is calculated based on the modified Prandtl extrusion theory. The failure of plastic extrusion occurs in the soft intercalation between quasi-rigid layers under the limit state. Considering the shortage of the shear stress solution of Prandtl extrusion theory in the x direction, considering the different boundary stress conditions, The stress component and the ultimate load on the interlayer surface in the soft intercalation are recalculated. The practical calculation formula for the ultimate load can take into account the friction conditions of the soft sandwich layer, the weight of the soil layer and the stress state around the interlayer, and so on. The calculated results are compared with those of other theoretical formulas. The calculated results show that, when soil weight is not taken into account, the law of variation of intercalation ultimate load with Prandtl method is basically the same as that calculated by Prandtl method, and when the influence of soil weight is taken into account, The calculated results of this method are similar to those of the standard method, but the influence of width on the ultimate load can be more clearly reflected when the interlayer is thick. In addition, the influence of the friction conditions of the upper and lower boundary of the interlayer on the ultimate load varies with the width to thickness ratio of the sandwich. For a certain thickness of intercalation, there is a critical width which is almost independent of the friction condition. The results of the study can provide a reference for the analysis of the bearing stability of the weak intercalation.
【作者单位】：中国矿业大学深部岩土力学与地下工程国家重点实验室;盐城工学院土木工程学院;
【基金】：国家重点基础研究发展计划(973计划)资助项目(No.2012CB026103) 国家自然科学基金资助项目(No.50974117)
【分类号】：TU43

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