| 临近边坡的条形基础地基极限承载力数值分析 |
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| 引用本文： | 郑刚,于晓旋,杜娟,尹鑫,周海祚,杨新煜.临近边坡的条形基础地基极限承载力数值分析[J].岩土力学,2018,39(10):3812-3820. |
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| 作者姓名： | 郑刚 于晓旋 杜娟 尹鑫 周海祚 杨新煜 |
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| 作者单位： | 1. 天津大学 建筑工程学院，天津 300072；2. 天津大学 滨海土木工程结构与安全教育部重点实验室，天津 300072； 3. 天津大学 水利工程仿真与安全国家重点实验室，天津 300072；4. 海南大学 土木建筑工程学院，海南 海口 570228 |
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| 基金项目： | 国家重点研发计划(No.2017YFC0805407)；国家自然科学基金(No. 51708405，No. 41630641)；天津市科技计划支撑计划项目(No. 16YDLJSF00040)。 |
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| 摘 要： | 建筑物或构筑物基础临近边坡置放的情况在实际工程中十分普遍，但目前对于临近边坡基础的地基承载力及破坏模式尚缺乏深入研究。采用不连续布局优化（DLO）极限分析法建立数值模型，分析边坡几何尺寸、土体参数和基础位置对临坡条形基础的极限承载力和边坡破坏模式的影响，并对国内外现行规范推荐的计算方法进行评价。结果表明：极限承载力随边坡高度和边坡倾斜角的增大而减小，当坡高超过临界高度后，极限承载力将不受其影响；极限承载力随土体黏聚力和内摩擦角的增大而提高，滑动面随黏聚力的增大而变浅，随内摩擦角的增大而变深；极限承载力随基础与坡肩相对距离的增大而提高，当基础置放位置超过某临界距离后极限承载力不受边坡影响。在土体强度高、坡角较大时，《建筑地基基础设计规范》规定的临坡基础最小置放距离偏于危险，设计时仍需考虑边坡对承载力的减损作用；在土体强度较低、坡角较小时，规范规定值偏于保守。美国AASHTO规范对边坡地基极限承载力的取值在砂土边坡时较为可靠，但其仅适用于坡面破坏模式的情况；饱和黏土边坡的承载力曲线有悖于理论解，对临界距离的规定同样存在低估。
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| 关 键 词： | 临近基坑 承载力 破坏模式 边坡稳定 安全距离 |
| 收稿时间： | 2017-02-20 |
Numerical analysis of ultimate bearing capacity of strip footings near slopes |
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| ZHENG Gang,YU Xiao-xuan,DU Juan,YIN Xin,ZHOU Hai-zuo,YANG Xin-yu.Numerical analysis of ultimate bearing capacity of strip footings near slopes[J].Rock and Soil Mechanics,2018,39(10):3812-3820. |
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| Authors: | ZHENG Gang YU Xiao-xuan DU Juan YIN Xin ZHOU Hai-zuo YANG Xin-yu |
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| Institution: | 1. School of Civil Engineering, Tianjin University, Tianjin 300072, China; 2. Key Laboratory of Coast Civil Structure Safety of Ministry of Education, Tianjin University, Tianjin 300072, China; 3. State Key Laboratory of Hydraulic Engineering Simulation and Safety, Tianjin University, Tianjin 300072, China; 4. College of Civil Engineering and Architecture, Hainan University, Haikou, Hainan 570228, China |
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| Abstract: | The footing placed on the top of a slope is common in geotechnical engineering practice. However, few studies were performed to study the bearing capacity and the failure mechanism of footing-slope systems. In this study, discontinuity layout optimization (DLO) is adopted to study the effects of geometry of the slope, soil properties and footing location on the limit load and the critical collapse mechanism. Evaluations are provided concerning the recommended estimating methods in present codes both at home and abroad. The results show that the ultimate bearing capacity decreases as the increasing slope height and slope angle, but the effects can be neglected when the slope height exceeds a critical value; the ultimate bearing capacity increases as the increasing soil strength. The failure slip becomes shallower with high soil cohesion, while the failure slip develops deeper with the increase of friction angle. The bearing capacity increases with the normalized footing distance of from the crest of slopes, and there is a critical normalized distance that makes the effect of slopes can be negligible. The specified value for the minimum distance suggested by the China Code for design of building footing is smaller than the critical distance with high soil strength and large slope angles, and the effect of slopes on the bearing capacity should be considered; conversely, the recommended designed distance tends to be conservative for low soil strength and small slope angles. In AASHTO code, the ultimate bearing capacity values for cohesiveless soil are reliable, but only face failure mode is considered; the recommended design chart is contrary to theoretical solution in cohesive soil. The normalized footing distance from the crest of slopes is underestimated in AASHTO code. |
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| Keywords: | near excavation bearing capacity failure modes slope stability safe distance |
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