西安建筑科技大学学报(自然科学版)

随着城市地铁线路穿越山地环境的日益增多,邻近边坡作为一种不利于施工的边界条件变得越发难以避免.边坡偏压影响下地铁车站基坑稳定性分析对于支护参数的选取与工程安全的控制具有重要意义.本文依托深圳轨道交通2号线莲塘口岸站工程,通过建立FLAC二维模型对不同偏压条件下的地表沉降、围护桩变形及剪应力变化规律进行分析.结果表明:地表沉降范围及最大沉降值均随边坡高度的增加而增大,偏压变化对于远坡桩的变形影响较小,但对于近坡桩的影响尤为明显.为定量分析偏压影响下地表及围护桩的变形规律,对结果进行了数据拟合并获得了地表最大沉降值、围护桩桩顶变形、围护桩最大变形及剪应力与边坡高度的关系公式.此外,分析表明随边坡高度的增加,基坑围护墙体的最大剪应力分布于基坑底部,此种情况在工程中需给予重点关注.

As more and more urban metro lines are designed to run through the mountainous environment, the situation of foundation pit set adjacent to the slope becomes more difficult to be avoided, which is an unfavorable boundary condition for construction.Ground settlement, pile deformation, and shear stress distribution under different bias pressure were analyzed in this paper based on 2D FLAC model.Simulated background and analysis parameters were set based on the practical project of Lian-Tang-Kou-An metro station of No.2 rail line in Shenzhen.Results show that the surface settlement scope and maximum settlement value increase as slope height, and the bias condition has lesser effect on the deformation of the far-slope pile than that of the near slope.In order to quantitatively analyze the deformation law under the influence of bias pressure, the data of simulation results were fitted to obtain the formula relationship between the slope height and the other parameters in terms of the maximum settlement value, the pile-top deformation, the maximum pile deformation and the shear stress.Moreover, the results show that with the increase of slope height, the maximum shear stress around the foundation wall is normally distributed at the bottom of the pit, which needs to be paid attention in practical engineering.

引言
1 工程概况
2 有限差分数值模拟
3 计算结果
4 结论

图1 莲塘口岸站基坑数值计算模型<br/>Fig.1 Numerical model of Liantangkouan metro station

图1 莲塘口岸站基坑数值计算模型
Fig.1 Numerical model of Liantangkouan metro station

表1 岩土体模型物理力学参数<br/>Tab.1 Physical and mechanical parameters of soil

表1 岩土体模型物理力学参数
Tab.1 Physical and mechanical parameters of soil

表2 支护结构参数<br/>Tab.2 Parameters of support structural elements

表2 支护结构参数
Tab.2 Parameters of support structural elements

表3 偏压强度分析计算方案<br/>Tab.3 Numerical model cases for bias strength analysis

表3 偏压强度分析计算方案
Tab.3 Numerical model cases for bias strength analysis

图2 模拟数据—实际监测数据对比<br/>Fig.2 Comparison of the monitor and simulated data

图2 模拟数据—实际监测数据对比
Fig.2 Comparison of the monitor and simulated data

图3 原型基坑周围地层沉降云图(单位:米)<br/>Fig.3 Nephogram of practical ground subsidence around the foundation(Unit: m)

图3 原型基坑周围地层沉降云图(单位:米)
Fig.3 Nephogram of practical ground subsidence around the foundation(Unit: m)

图4 远坡处地表沉降影响范围<br/>Fig.4 Surface settlement scope at the area away from the slope

图4 远坡处地表沉降影响范围
Fig.4 Surface settlement scope at the area away from the slope

图5 远坡处地表最大沉降值拟合曲线<br/>Fig.5 Fit curves of maximum surface settlement at the area away from the slope

图5 远坡处地表最大沉降值拟合曲线
Fig.5 Fit curves of maximum surface settlement at the area away from the slope

图6 不同偏压强度下围护桩深与桩变形关系曲线<br/>Fig.6 Relation curves between pile deformation and buried depth under different bias conditions

图6 不同偏压强度下围护桩深与桩变形关系曲线
Fig.6 Relation curves between pile deformation and buried depth under different bias conditions

图7 不同偏压强度下近坡桩最大水平变形拟合曲线<br/>Fig.7 Fit curves of maximum horizontal deformation of near-slope pile under different bias conditions

图7 不同偏压强度下近坡桩最大水平变形拟合曲线
Fig.7 Fit curves of maximum horizontal deformation of near-slope pile under different bias conditions

图8 不同偏压强度下围护桩顶变形拟合曲线<br/>Fig.8 Fit curves of pile-top deformation under different bias conditions

图8 不同偏压强度下围护桩顶变形拟合曲线
Fig.8 Fit curves of pile-top deformation under different bias conditions

图9 基坑围护墙土层最大剪应力分布云图(单位: Pa)<br/>Fig.9 Nephogram of max shear stress within the ground near the retaining wall(Unit: Pa)

图9 基坑围护墙土层最大剪应力分布云图(单位: Pa)
Fig.9 Nephogram of max shear stress within the ground near the retaining wall(Unit: Pa)

图10 土层最大剪应力与边坡高度关系曲线<br/>Fig.10 Relation curves between max shear stress and slope height

图10 土层最大剪应力与边坡高度关系曲线
Fig.10 Relation curves between max shear stress and slope height

图11 不同偏压强度下基坑周围土压力分布曲线<br/>Fig.11 Soil pressure distribution curve around the foundation pit under different bias conditions

图11 不同偏压强度下基坑周围土压力分布曲线
Fig.11 Soil pressure distribution curve around the foundation pit under different bias conditions

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备注

引言

1 工程概况

2 有限差分数值模拟

3 计算结果

4 结论

期刊信息