成都地区膨胀土基坑支护技术研究

发布时间：2018-01-04 01:22

本文关键词：成都地区膨胀土基坑支护技术研究　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：进行建筑基础建设时,基坑的稳定性对工程的成败具有决定性作用。成都东部台地地区众多基坑支护设计和施工往往会遇到具有膨胀性的成都粘土,这类基坑开挖问题,一直以来就是困扰工程建设的重点和难点问题。本文在总结课题相关研究现状的基础上,首先研究了膨胀土的基本性质及其在成都地区表现的特性；然后对膨胀土基坑边坡进行极限平衡法数值分析,根据边坡安全系数研究其参数敏感性、裂隙影响规律及支护设计效果；最后基于成功案例,综合安全、经济及施工工艺方面综合总结出不同深度膨胀土基坑适宜的支护技术。文章主要结论如下：(1)通过一系列的膨胀土地层的各种参数以及基坑边坡的敏感性分析表明,高边坡稳定性的主要因素中膨胀土的凝聚力(C值)的对稳定性的影响比产生内摩擦角(Φ值)要大;(2)张裂隙影响分析表明,在坡顶不同位置处产生裂隙并向下发展过程中,对边坡整体稳定性影响会由无影响、加重影响到稳定影响阶段,其中开始影响深度可作为裂隙预警基础值,而稳定影响深度可作为裂隙发展最不利深度的参考值；(3)支护效果对比分析表明,在满足其它条件下,进行坡底锁脚支护设计是最经济方式,支护反力最有效的作用区域为距离坡脚1/3坡高区域,距离坡顶1/3坡高区域不建议作为支护合力设计作用范围；(4)较浅基坑(5m)实例应用分析表明,其宜采用锚喷结合应力卸荷槽加矮脚墙(脚墙高度不大于0.5m)的方式进行支护,粘土层中的锚杆(土钉)只考虑加工倒剌,不宜注浆；(5)中深基坑(5～10m)实例应用分析表明,当其粘土厚度不大于5.0mm且粘土层处于坑壁下部其支护方式宜采用锚喷结合卸荷槽加高脚墙(脚墙高度在0.5m～1.0m范围)的方式进行支护,粘土层中的锚杆(土钉)只考虑加工倒刺。不宜采用注浆方式。若粘土层处于坑壁上部,则支护方式宜采用排桩及桩间土支护；(6)深基坑(10m)实例应用分析表明,较适宜选择采用锚拉桩加桩间土支护方式进行支护。
[Abstract]:The construction of the building foundation, the stability of the foundation pit is decisive to the success of the project. Many areas in eastern Chengdu platform foundation pit design and construction are often encountered with expansive clay in Chengdu, this kind of foundation pit excavation, has been plagued by key and difficult problem in engineering construction. Based on the summary of related research topics on the current situation, we first study the basic properties of expansive soil and its characteristics in Chengdu area; then the expansive soil slope by numerical analysis of limit equilibrium method, according to the research of the slope safety coefficient parameter sensitivity, influence law of fracture and supporting design effect; finally based on the successful case, comprehensive security, economy and construction technology comprehensive summarized suitable foundation pit supporting technology in different depth expansion. The main conclusions are as follows: (1) through a series of land expansion The various parameters of layer and foundation pit slope sensitivity analysis showed that the main factors of the cohesion of the expansive soil slope stability in (C) impact on stability than the internal friction angle (a value) to large (2); Zhang Liexi effect analysis showed that the cracks in the top of the hill and down the development process at different positions in the influence of no influence on the overall stability of the slope, increasing impact to affect the stability of stage, which can be used as a crack began to affect the depth based early warning value, and can be used as a stable influence depth of crack development the most unfavorable depth reference value; (3) analysis of the supporting effect compared to meet other conditions, to the bottom of the slope lock foot support design is the most economical way, supporting regional force the most effective distance for 1/3 high slope slope area, from the top of the hill 1/3 high slope area is not recommended as the supporting force design scope; (4) shallow foundation pit (5 M) example show that it should be sprayed with the stress relief groove and short leg wall (foot wall height not more than 0.5m) by way of supporting anchor in clay layer (soil) only consider the processing of barbed, not grouting; (5) deep foundation pit (5 ~ 10m) analysis the application shows that, when the thickness is not greater than 5.0mm and the clay layer in the pit wall of the lower part of its supporting method should be adopted with the anchor unloading groove heightening foot wall (foot wall height in 0.5m ~ 1.0m) by way of supporting anchor in clay layer (soil) should not only consider the processing of barbs. The grouting way. If the clay layer in the upper part of the pit wall, supporting way should adopt the pile and soil between piles supporting deep foundation pit; (6) (10m) analysis shows that the application, choose suitable anchor pile and soil between piles supporting support.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU443;TU753

【相似文献】