花岗岩残积土三轴试验应变局部化特征研究

发布时间：2018-07-05 12:39

本文选题：花岗岩残积土 + 三轴试验　；参考：《华南理工大学》2013年硕士论文

【摘要】：花岗岩残积土虽然是一种特殊土，有其区别于普通粘土的特殊性质，但是在实际工程及室内试验中也经常碰到应变局部化的问题。以深圳地区某基坑取得的花岗岩残积土的破坏形态为主要研究对象，通过三轴试验及无侧限压缩试验，研究压实度、固结度、内聚力、摩擦力对花岗岩残积土剪切带形成的影响。在试验的基础上，通过PFC2D数字模拟的方法来尝试分析土样颗粒细观参数对剪切带形成的影响。本文的主要工作及结果如下： 1、不同压实度正常固结试样的三轴固结不排水试验表明，不同压实度的重塑正常固结花岗岩残积土试样均出现鼓状破坏，压实度对正常固结重塑花岗岩残积土剪切带的产生无明显影响。 2、不同超固结状态试样的三轴固结不排水试验表明，当试样的超固结比为2、3、4时，试样都发生鼓状破坏，这三种超固结比状态对重塑花岗岩残积土局部化剪切带的产生无明显影响。 3、饱和试样与加水泥试样的无侧限压缩试验表明，当重塑花岗岩残积土试样的内聚力增大时，试样易产生类似岩石的压剪破坏模式。重塑花岗岩残积土粘聚力变大时，容易产生贯穿的剪切带。 4、加砂试样的三轴固结不排水试验表明，当重塑花岗岩残积土试样的摩擦力增大时，试样产生明显的局部化剪切带，摩擦力是控制重塑花岗岩残积土剪切带产生的主要因素。 5、通过PFC软件的模拟进一步说明了摩擦力是控制重塑花岗岩残积土剪切带产生的主要因素。
[Abstract]:Although granite residual soil is a special kind of soil, it is different from ordinary clay in its special properties, but it often encounters the problem of strain localization in practical engineering and laboratory tests. Taking the failure pattern of granite residual soil obtained from a foundation pit in Shenzhen area as the main research object, the compaction, consolidation and cohesion of granite residual soil were studied by triaxial test and unconfined compression test. The influence of friction on the formation of shear zone of granite residual soil. On the basis of the experiment, the influence of soil particle meso parameters on the formation of shear band is analyzed by PFC2D numerical simulation method. The main work and results of this paper are as follows: 1. The undrained triaxial consolidation tests of normal consolidation samples with different compaction degrees show that the remolded normal consolidated granite residual soil samples with different compaction degrees have bulging failure. The compaction degree has no significant effect on the formation of shear zone of normal consolidated remolded granite residual soil. 2. The triaxial consolidation undrained test of samples in different overconsolidated states shows that when the overconsolidation ratio of the sample is 2 渭 3,4, The three kinds of overconsolidation ratio states have no obvious influence on the formation of localized shear zone of remolded granite residual soil. 3. The unconfined compression tests of saturated and cemented samples show that there is no obvious effect on the formation of the local shear zone of the remolded granite residual soil. When the cohesive force of the remolded granite residual soil increases, the specimen is prone to produce a compressive shear failure model similar to that of the rock. When the cohesive force of remolded granite residual soil becomes larger, it is easy to produce a penetrating shear zone. 4. The triaxial consolidation undrained test of sand-added sample shows that when the friction force of remolded granite residual soil specimen increases, The specimen produces obvious localized shear bands, The friction force is the main factor to control the shear zone of remolded granite residual soil. 5. The simulation of PFC software further shows that the friction force is the main factor to control the formation of shear zone of remolded granite residual soil.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU41

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