济南市典型土岩双元基坑破坏模式及其支护结构选型研究

发布时间：2018-05-20 04:14

本文选题：土岩双元基坑边坡 + 破坏模式　；参考：《山东大学》2017年硕士论文

【摘要】：基于济南市土岩地质条件,运用PLAXIS 3D有限元软件,分析典型土岩双元地层结构基坑边坡破坏模式,研究微型桩复合土钉墙与吊脚桩支护结构的变形及受力规律,取得结论如下:1、破坏模式土+全风化岩边坡可视为整体土层,破坏模式为圆弧滑动面;土+全风化岩石+强风化岩石型边坡,坡率大于1:0.8时,土层、全风化岩层和部分强风化岩层发生圆弧滑动破坏;坡率小于1:0.8时,土层全风化岩层发生圆弧滑动破坏,破坏面底端与强风化岩层界面相切,强风化岩层内不发生破坏。土+全风化岩石+强风化岩石+中风化岩石型基坑,坡率大于1:0.8时,土层、全风化岩层和部分强风化岩层发生圆弧滑动破坏;坡率小于1:0.8时,土层全风化岩层发生圆弧滑动破坏,破坏面底端与强风化岩层界面相切;中风化岩层始终不发生破坏。2、微型桩复合土钉墙支护结构相对桩锚支护结构来说,桩径小,桩身材料强度高,桩间距紧密;变形控制效果略弱于桩锚支护结构,内力控制效果优于桩锚支护结构。内力峰值状态在开挖至中风化岩层界面时出现,变形峰值状态在开挖至基坑底时出现,破坏面为一条位于土层和碎石层内部的圆弧滑动面,底端相切于中风化岩界面。3、吊脚支护桩结构桩体的变形以及内力峰值状态在开挖至中风化岩层界面时出现。破坏面为一条位于土层内部的圆弧滑动面,底端相切于土岩界面,中风化岩层不会破坏。吊脚桩嵌固1.5m和岩肩宽度0.5-1m为吊脚支护桩结构最佳构造,利于内力和位移控制。
[Abstract]:Based on the geological conditions of soil and rock in Jinan city, the failure mode of foundation pit slope of typical soil-rock double-element formation structure is analyzed by using PLAXIS 3D finite element software, and the deformation and force law of micro-pile composite soil nailing wall and hoisting pile supporting structure are studied. The results are as follows: 1. The soil weathered rock slope can be regarded as a whole soil layer, the failure mode is a circular sliding surface, and the soil layer with a slope ratio greater than 1: 0.8 is strongly weathered rock slope with soil weathering rock. When the slope ratio is less than 1: 0.8, the total weathered rock layer will be destroyed by arc sliding, the interface between the bottom of the failure surface and the strongly weathered rock layer will be tangent, and the strong weathered rock layer will not be destroyed. When the slope ratio is greater than 1: 0.8, the circular sliding failure occurs in soil layer, weathered rock layer and part of strongly weathered rock layer, and when the slope ratio is less than 1: 0.8, The total weathering rock layer of soil layer is destroyed by arc sliding, and the bottom end of the failure surface is tangent to the interface of strongly weathered rock layer, and the medium weathered rock layer does not occur damage of .2. the pile diameter is small relative to the pile anchor support structure of the micro-pile composite soil nailing wall. The effect of deformation control is slightly weaker than that of pile-anchor support structure, and the effect of internal force control is better than that of pile-anchor support structure. The peak state of internal force appears at the interface between excavation and middle weathering strata, and the peak state of deformation occurs when excavating to the bottom of foundation pit. The failure surface is a circular slip surface located in the soil layer and the gravel layer. The bottom end is tangent to the interface of medium weathered rock. The deformation of pile body and the peak state of internal force of suspending support pile structure appear at the interface between excavation and middle weathering strata. The failure surface is a circular slip surface located inside the soil layer, and the bottom end is cut to the interface of the earth rock, and the middle weathered rock layer will not be destroyed. The optimum structure of hoisting support pile is 1.5 m fixed and 0.5-1m width of rock shoulder, which is favorable for internal force and displacement control.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753

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