西安建筑科技大学学报(自然科学版)

在无载复合地基侧向开挖离心机试验基础上建立了数值模拟模型,基于Winkler地基模型,根据桩土的位移变形协调方程,采用两阶段法求解复合地基单桩的水平位移,并与数值模拟结果进行对比.在数值模拟基础上,改变复合地基的置换率,得到了不同置换率以及不同开挖深度下的单桩的水平位移,模拟并对比了在复合地基至支护结构不同距离情况下的土体最大水平位移,研究结果表明:①将复合地基视为均质土体,通过二阶段法求解复合地基单桩位移的方法可行; ②当复合地基桩间距大于4倍单桩桩径时,复合地基对于单桩的水平位移影响较小.在设计支护结构时,当基坑深度小于5 m时,可以忽略复合地基与土体间的相互影响,深度大于5 m时,应充分考虑复合地基的影响; ③当复合地基距离支护结构的距离在基坑开挖深度的0.8倍以内时,其对土体的侧向加固作用才有较好效果.

Based on the lateral excavation of unloaded composite foundation centrifuge test, a numerical simulation model is established. Based on Winkler foundation model, the two-stage method is used to calculate the horizontal displacement of single pile based on the displacement-deformation coordination equation of pile-soil, and compared with the numerical simulation results. Based on numerical simulation, by changing the displacement of composite foundation, different displacements and horizontal displacements of single pile under different excavation depths were obtained. The horizontal displacement is calculated under different distances from composite foundation to the retaining wall. The results can be concluded as follows: ①The applicability of regarding composite foundation as a homogeneous soil to solve the horizontal displacement of Single Pile is proved. ②When the distance between piles is greater than 4 times of single pile diameter, the horizontal displacement of composite foundation has little effect on the horizontal displacement of pile; when the depth of the foundation pit is less than 5m, the interaction between the composite foundation and the soil can be neglected; and when the depth is more than 5m, the influence of the composite foundation should be taken into full consideration. ③When the distance of the composite foundation from the supporting structure is within 0.8 times of the excavation depth of the foundation pit, it has a better effect on the lateral reinforcement of the soil.

引言
1 模型试验
2 被动单桩的分析方法
3 复合地基置换率对桩位移影响分析
4 基坑开挖深度与复合地基桩位移
5 复合地基至支护结构距离对挡墙位移的影响
6 结论

图1 台仓平面位置图
Fig.1 Plan of stage-bin

图2 台仓顶面标高图<br/>Fig.2 Elevation of top and bottom of stage-bin

图2 台仓顶面标高图
Fig.2 Elevation of top and bottom of stage-bin

图3 双排桩与CFG桩关系示意图<br/>Fig.3 Double-row pile and CFG composite foundation

图3 双排桩与CFG桩关系示意图
Fig.3 Double-row pile and CFG composite foundation

表1 福建砂物理力学参数<br/>Tab.1 Physical and mechanical parameters of Fujian sand(F. S.)

表1 福建砂物理力学参数
Tab.1 Physical and mechanical parameters of Fujian sand(F. S.)

图4 模型试验示意图(单位:mm)<br/>Fig.4 Foundation model(Unit: mm)

图4 模型试验示意图(单位:mm)
Fig.4 Foundation model(Unit: mm)

表2 模型挡墙和桩相关参数<br/>Tab.2 Relevant parameters of simulated supporting structure and piles

表2 模型挡墙和桩相关参数
Tab.2 Relevant parameters of simulated supporting structure and piles

图5 单元网格划分
Fig.5 Cell mashing

图6 模型试验与数值模拟挡墙水平位移对比<br/>Fig.6 Comparison of horizontal displacement between model test and numerical simulation

图6 模型试验与数值模拟挡墙水平位移对比
Fig.6 Comparison of horizontal displacement between model test and numerical simulation

图7 单桩水平位移结果比较<br/>Fig.7 Comparation of single-pile horizontal displacements

图7 单桩水平位移结果比较
Fig.7 Comparation of single-pile horizontal displacements

图8 不同置换率下桩上部水平位移<br/>Fig.8 Horizontal displacement of pile at different replacement rates

图8 不同置换率下桩上部水平位移
Fig.8 Horizontal displacement of pile at different replacement rates

图9 不同置换率下桩顶最大水平位移比较<br/>Fig.9 Maximum displacement of pile under different replacement rates

图9 不同置换率下桩顶最大水平位移比较
Fig.9 Maximum displacement of pile under different replacement rates

图10 不同开挖深度下的单桩水平位移<br/>Fig.10 Horizontal displacement of Single pile under different excavation depth

图10 不同开挖深度下的单桩水平位移
Fig.10 Horizontal displacement of Single pile under different excavation depth

图11 有无复合地基下桩位置处土体的位移差<br/>Fig.11 The displacement difference of the soil at the position of the pile

图11 有无复合地基下桩位置处土体的位移差
Fig.11 The displacement difference of the soil at the position of the pile

图12 土体的最大位移差与开挖深度关系<br/>Fig.12 Relationship between maximum displacement of soil and depth of excavation

图12 土体的最大位移差与开挖深度关系
Fig.12 Relationship between maximum displacement of soil and depth of excavation

图13 复合地基至挡墙不同距离挡墙水平位移<br/>Fig.13 Horizontal displacement at different distances from composite foundation to the retaining wall

图13 复合地基至挡墙不同距离挡墙水平位移
Fig.13 Horizontal displacement at different distances from composite foundation to the retaining wall

图14 复合地基至挡墙不同距离挡墙最大水平位移比较<br/>Fig.14 Comparison of the maximum horizontal displacement at different distances from composite foundation to the retaining wall

图14 复合地基至挡墙不同距离挡墙最大水平位移比较
Fig.14 Comparison of the maximum horizontal displacement at different distances from composite foundation to the retaining wall

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备注

引言

1 模型试验

2 被动单桩的分析方法

3 复合地基置换率对桩位移影响分析

4 基坑开挖深度与复合地基桩位移

5 复合地基至支护结构距离对挡墙位移的影响

6 结论

期刊信息