【作者】 蓝日彦；

【导师】 吴恒；

【作者基本信息】 广西大学 ， 岩土工程， 2002， 硕士

【摘要】 涉及因素众多的城市深基坑工程往往事故率较高，说明基坑工程设计理论尚不够完善，还有待于提高与改进。但目前由子基坑工程工期、资金等诸多因素的限制，对信息化设计与施工有重要作用的现场原型试验因试验条件不易控制、投资大且见效慢而难以实施。室内模型试验因成本低、试验周期短、难度小、参数选择具有可控性和灵活性等优点被作为有效的研究手段。国内外学者也曾用模型试验进行过深基坑模拟试验研究，但多集中在以砂土作为填料的板桩支护模拟。 本文总结了前人研究成果，构筑大型室内深基坑排桩支护试验模型，在均质及层状土层结构地基上，设计了密排桩、疏排桩及无支护三种不同支护型式，采用模拟开挖与坡顶均布加荷方式，进行了模拟基坑开挖和破坏性的两个阶段试验，对三种不同支护型式的土压力与桩位移、土体应力与变形、桩土共同作用及支护结构失稳破坏进行系统研究。 研究结果表明，基坑边坡土体具有地基整体剪切变形破坏的特点，系渐进破坏的过程；支护桩侧向变形是桩嵌固深度、荷载大小、土体强度参数变量的函数；土体的位移和支护桩的位移满足变形协调条件。同时试验研究也获得了在不同支护型式下土压力、土体应力的分布及动态变化规律，研究成果对基坑工程的设计与施工具有指导作用。更多还原

【Abstract】 Because deep foundation pit engineering in urban involved many factors, its accident ratio is very high, which indicates that foundation pit engineering design theory isn’t perfect and needs improve. But due to time limit and fund factor of foundation pit project and because test condition is hard to control, and due to test needs much fund and takes effect slowly, field in-situ test that is important to information design and construction is difficult to do .As effective research means, laboratory model test is used due to the following reasons: low cost, short test period, easy to do, test parameter flexible selected and easily to control. Some researchers at home and aboard apply model test to deep foundation pit simulation study, most of them are sheeting pile timbering deep foundation pit simulation which is stuffed with sand.In the paper, other research results are summarized, and a big test model indoor of row pile retaining and protecting deep foundation pit is designed. For homogeneous soil or samdwich soil structure three different retaining and protecting kinds: dense pile, thin pile and without pile are designed, using excavation simulation and loading on the top of slope,the model test is divided into two stages: foundation pit excavation simulation stage and destroy test stage. In this paper, for three different retaining and protecting kinds, the relation between soil pressure and displacement of piles, the relation between soil stress and strain, interaction of pile and soil and retaining and protecting loss-stability destroy are systemic studied.Research results show that foundation pit slope soil structure destroy characteristic is subgrade shear strain destroy, namely, it is gradually destroy. Lateral displacement of retaining and protecting piles has relations with embed depth, load grade and strength index parameter. Soil displacement and timbering pile displacement are in harmony with deformation. At the same time, some change regularity about earth pressure, soil stress distribution and dynamic changing are obtained. In a word, research result is useful to instruct foundation pit project’s design and construction.更多还原