| 劲芯水泥土桩承载路堤渐进式失稳破坏机制 |
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| 引用本文： | 张振,张朝,叶观宝,王萌,肖彦,程义.劲芯水泥土桩承载路堤渐进式失稳破坏机制[J].岩土力学,2020,41(6):2122-2131. |
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| 作者姓名： | 张振 张朝 叶观宝 王萌 肖彦 程义 |
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| 作者单位： | 1. 同济大学 地下建筑与工程系，上海 200092；2. 同济大学 岩土及地下工程教育部重点实验室，上海 200092；
3. 杭州都市高速公路有限公司，浙江 杭州 310024 |
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| 基金项目： | 国家自然科学基金（No.51508408，No.41772281）；中央高校基本科研业务费专项资金（No.22120180106）；浙江省交通投资集团有限公司科技项目计划（No.201813）。 |
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| 摘 要： | 劲芯水泥土桩是一种软土地基处理的新方法，近年来已成功应用于公路、铁路路基处理工程中。然而由于人们对其承载路堤的失稳破坏机制认识不足，无法正确指导设计。采用反映桩体材料破坏后特征的应变软化模型，模拟劲芯水泥土桩承载路堤失稳破坏1g模型试验，通过分析路堤失稳破坏过程中桩体塑性区的开展和桩身受力的变化情况，研究了桩体的破坏顺序及其破坏模式。结果表明：路堤失稳过程中，劲芯水泥土桩并非同时发生破坏，路面正下方桩体首先发生受压破坏，坡面下方桩体自坡脚至坡肩依次发生弯剪破坏；由于桩体的存在，路基中滑动面并非完全穿过桩体破坏位置。基于桩体破坏顺序、破坏模式、受力情况变化，以及荷载传递规律，阐释了劲芯水泥土桩承载路堤渐进式失稳破坏机制。采用现行规范中基于残余强度的柔性桩处理方法，计算的安全系数与试验结果较为接近，但其适用性还需做进一步研究。
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| 关 键 词： | 劲芯水泥土桩 路堤 应变软化 渐进式破坏 数值模拟 |
| 收稿时间： | 2019-06-17 |
| 修稿时间： | 2019-11-21 |
Progressive failure mechanism of stiffened deep mixed column-supported embankment |
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| ZHANG Zhen,ZHANG Zhao,YE Guan-bao,WANG Meng,XIAO Yan,CHENG Yi.Progressive failure mechanism of stiffened deep mixed column-supported embankment[J].Rock and Soil Mechanics,2020,41(6):2122-2131. |
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| Authors: | ZHANG Zhen ZHANG Zhao YE Guan-bao WANG Meng XIAO Yan CHENG Yi |
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| Institution: | 1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;
2. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092, China;
3. Hangzhou Metropolitan Expressway Co., Ltd., Hangzhou, Zhejiang 310024, China |
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| Abstract: | Stiffened deep mixed (SDM) column is a new ground improvement method for soft soil foundations, and has been successfully applied in ground improvement projects in roadways and railways recently. However, due to inadequate understanding of the instability mechanism of the embankment supported by SDM column, there is no mature theory to guide the design. In this paper, strain-softening model, which can reflect the post-failure behavior of column materials, was used to model the scale-down 1g model test of stability of SDM column-supported embankment. The sequence and modes of SDM column failure were investigated through examining the developments of plastic zone and force changes in SDM columns in the failure process. The results showed that the columns did not fail simultaneously in the process of embankment failure. The columns near the center of embankment failed by compression at first, followed by the sequence bending failures of the columns under embankment slope from the toe to the shoulder. The slip surface did not completely pass through the failure positons of the columns due to the existence of columns. Accordingly, the failure mechanism of SDM column-supported embankment was interpreted. The semi-rigid column method based on residual strength in the currently-used code yielded close factor of safety to the model test, but its feasibility still needs a further study. |
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| Keywords: | stiffened deep mixed column embankment strain-softening progressive failure numerical simulation |
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