| 土钉抗拔试验过程中钉周土体应力变化研究 |
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| 引用本文： | 苏立君,廖红建,殷建华.土钉抗拔试验过程中钉周土体应力变化研究[J].岩土力学,2011,32(Z1):124-128. |
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| 作者姓名： | 苏立君 廖红建 殷建华 |
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| 作者单位： | 西安建筑科技大学土木工程学院;西安交通大学土木工程系;香港理工大学土木工程系 |
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| 基金项目： | 国家自然科学基金资助(No.50979087) |
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| 摘 要： | 土钉的抗拔强度是土钉支护结构设计需要用到的重要参数。抗拔强度的大小取决于拔出过程中作用于土钉表面的法向应力的大小。通过室内模型抗拔试验以及三维有限元分析,研究了钻孔灌注型土钉在钻孔、注浆及拔出过程中土钉杆周围土体中的应力变化情况。研究发现,对于钻孔灌注型土钉,孔周土体中的应力在钻孔结束时几乎全部释放掉;对于低压灌浆土钉,灌浆结束到浆体硬化的过程中土钉杆周围土体中的应力没有得到有效恢复;拔出过程中,由于土体的剪胀变形受到约束,土钉周围土体中的应力随着拔出位移的增加逐渐增加,从而导致抗拔应力的增加,说明土的剪胀性对钻孔灌注型土钉来说非常重要,对于低剪胀性土,需要通过增加灌浆压力等方法对钻孔过程中释放掉的应力进行补偿。
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| 关 键 词： | 土钉 抗拔强度 法向应力 有限元 |
| 收稿时间： | 2010-12-02 |
Investigation on stress variation in soil surrounding a soil nail during installation and pull-out |
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| SU Li-jun,LIAO Hong-jian,YIN Jian-hua.Investigation on stress variation in soil surrounding a soil nail during installation and pull-out[J].Rock and Soil Mechanics,2011,32(Z1):124-128. |
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| Authors: | SU Li-jun LIAO Hong-jian YIN Jian-hua |
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| Institution: | 1. School of Civil Engineering, Xi’an University of Architecture & Technology, Xi’an 710055, China; 2. Department of Civil Engineering, Xi’an Jiaotong University, Xi’an 710049, China; 3. Department of Civil Engineering, the Hong Kong Polytechnic University, Hong Kong, China |
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| Abstract: | Pull-out strength of a soil nail is an important parameter in the design of a soil nailing system. The pull-out strength is determined by the normal stress acting on the soil nail surface during pull-out. The variation of normal stress in soil surrounding a drill-and-grout soil nail during drilling, grouting and pull-out is studied through both laboratory pull-out tests and numerical simulation. It is found that for a drill-and-grout soil nail, most of the normal stress in the soil surrounding the hole is released after drilling. For a soil nail grouted under low pressure, the normal stress does not substantially recover after the nail is installed. During pull-out, the normal stress acting on the nail increases with the increase in pull-out distance because of the constrained dilatancy of the soil surrounding the nail, which eventually increases the pull-out resistance. It is indicated that the dilatancy of the soil is very important to a drill-and-grout soil nail. For soils with low dilatancy, further measures, such as high pressure grouting should be employed to compensate the released stress during drilling. |
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| Keywords: | soil nail pull-out strength normal stress finite elements |
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