主动平移模式下墙后非饱和砂土破坏模式及侧向土压力分布试验研究

邓波; 杨明辉; 赵明华

doi:10.11779/CJGE20211280

主动平移模式下墙后非饱和砂土破坏模式及侧向土压力分布试验研究 English Version

邓波^{1, 3,},
杨明辉^{2, 3, ,},
赵明华³

1.
南华大学土木工程学院, 湖南衡阳 421001
2.
厦门大学建筑与土木工程学院, 福建厦门 361005
3.
湖南大学土木工程学院, 湖南长沙 410082

基金项目:

湖南省自然科学青年基金项目 2021JJ40460

国家自然科学基金项目 51678230

湖南省教育厅科学研究项目一般项目 210SJY090

详细信息

作者简介:
邓波(1991—)，男，博士，讲师，主要从事非饱和土力学理论与应用等方面的研究工作。E-mail: parl_d@126.com

通讯作者:
杨明辉, E-mail: yamih@hnu.edu.cn

中图分类号: TU432
计量
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出版历程
- 收稿日期: 2021-10-31
- 网络出版日期: 2023-02-03
- 发布日期: 2021-10-31
- 刊出日期: 2022-12-31

Experimental study on failure mode and lateral earth pressure distribution of unsaturated sand behind retaining walls under active translation mode

DENG Bo^{1, 3,},
YANG Minghui^{2, 3, ,},
ZHAO Minghua³

1.
School of Civil Engineering, University of South China, Hengyang 421001, China
2.
School of Architecture and Civil Engineering, Xiamen University, Xiamen 361005, China
3.
College of Civil Engineering, Hunan University, Changsha 410082, China

摘要

摘要: 在主动平移模式下，开展一系列不同墙面粗糙度和砂土含水率情况下刚性挡墙主动土压力室内模型试验，通过渗压计和土压力盒分别监测了基质吸力和土压力的变化，并基于DIC图像关联技术获取破裂面位置，进而分析了基质吸力和界面粗糙度对主动土压力和土体破裂面形状的影响。试验结果表明：随着含水率增加，砂土破裂面逐渐向外移，原因在于当砂土基质吸力大于其进气值时，吸应力随基质吸力的增大而减小，进而使土体抗剪强度降低；达到主动极限状态后，破裂面过墙踵，但比库仑破裂面要浅，二者差异随基质吸力减少而增小；墙土界面摩擦对滑动破裂面形状的影响很小。此外，主动土压力在墙体中上部区域，随着深度增加而近似呈线性增大，但在墙踵附近区域，松砂传递的摩阻力使土压力出现略有减小；实测主动土压力值始终小于库仑主动土压力值，其差值随着含水率的增大而增大；相比摩擦角的影响，吸应力对土压力作用更为明显。
- 非饱和土 /
- 主动土压力 /
- 界面粗糙度 /
- 刚性挡墙 /
- 模型试验
Abstract: Under the active translation mode, a series of laboratory model tests on the active earth pressure against rigid retaining walls with different wall roughnesses and water contents of backfill are carried out, in which the matric suction and earth pressure are monitored by embedding the piezometer and earth pressure cell, respectively, and the position of the failure surface is obtained by using the DIC technique, and the effects of the matric suction and interface roughness on the earth pressure and the shape of the failure surface are discussed. The test results show that with the increase of the water content, the failure surface tends to move outward. The reason is that when the matric suction of sand is greater than its air entry value, the suction stress decreases with the increase of the matric suction, which in turn reduces the shear strength of the soil. After reaching the active limit state, the fracture surface passes the wall heel but is shallower than the Coulomb failure surface, and the difference between them increases with the decrease of the matric suction. The wall-soil interface friction has a few effects on the shape of failure surface. Furthermore, in the middle and upper parts of the wall, the active earth pressure increases approximately linearly with the increase of depth, but in the area near the heel of the wall, the earth pressure shows a slight decrease, which is mainly caused by the frictional resistance transmitted by loose sand. The measured active earth pressure is always smaller than that of Coulomb active earth pressure, and the difference increases with the increase of the water content. Compared with the influences of the friction angle, the suction stress has a more obvious effect on the earth pressure.
- unsaturated soil /
- active earth pressure /
- interface roughness /
- rigid retaining wall /
- model test

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图 1 试验系统结构图

Figure 1. Setup of testing system

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图 2 轴承传动系统

Figure 2. Bearing drive system

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图 3 渗压计标定装置

Figure 3. Calibration device of piezometer

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图 4 渗压计标定结果

Figure 4. Calibrated results of piezometer

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图 5 渗压计位置布设

Figure 5. Location of piezometers

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图 6 土压力盒位置布设

Figure 6. Location of earth pressure cells

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图 7 DIC分析平面区域

Figure 7. Planar area for conducting DIC analysis

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图 8 颗粒级配曲线

Figure 8. Grain-size distribution curve

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图 9 基质吸力与体积含水率的关系

Figure 9. Relationship between matric suction and volumetric water content

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图 10 砂体整体下沉

Figure 10. Integral settlements of sand

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图 11 挡墙移动过程中破坏面的演化过程

Figure 11. Evolution process of failure surface during movement of retaining wall

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图 12 破裂面几何形状的确定方法

Figure 12. Method for determining geometry of failure surface

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图 13 墙后土体位移-时间曲线

Figure 13. Displacement-time curves of soil behind wall

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图 14 不同工况下砂土破裂面

Figure 14. Failure surfaces of sand under different test conditions

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图 15 各试验工况的基质吸力值

Figure 15. Values of matric suction of various test conditions

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图 16 随墙体移动的土压力分布

Figure 16. Distribution of earth pressure with wall movement

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表 1 有效剪切强度参数

Table 1 Effective shear strength parameters

砂土-光滑墙面砂土-粗糙墙面砂土

${c'_{\text{a}}}$ /kPa δ'/(°) ${c'_{\text{a}}}$ /kPa δ'/(°) c'/kPa $\varphi '$ /(°)

0 7.4 0 14 0 33.6

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表 2 试验工况编号

Table 2 Number of test conditions

墙面类型含水率

0% 3% 5% 8%

光滑面 LEP1 LEP3 LEP5 LEP7

粗糙面 LEP2 LEP4 LEP6 LEP8

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