| 基坑降水总应力变化时有效应力增量和沉降量计算 |
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| 引用本文： | 张莲花,李荣强,刘德坊.基坑降水总应力变化时有效应力增量和沉降量计算[J].中国地质灾害与防治学报,2001,12(1):75-77. |
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| 作者姓名： | 张莲花 李荣强 刘德坊 |
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| 作者单位： | 1. 成都理工学院工程地质研究所，四川 成都 610059
2. 深圳市工程地质勘察研究院，广东 深圳 518026 |
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| 摘 要： | 针对基坑降水引起地面沉降计算值比实际值偏大的情况，本文系统分析了潜水和承压含水层在降水后，不同条件下土中总应力及有效应力的计算。基坑降水后土体中的总应力不是通常认为的一成不变。特别是基坑降水中常遇到的降低潜水含水层水头的情况，总应力是减小的，有效应力增量值也小于孔隙水压力下降值。对比分析了通常采用的不变原理和本文提出的可变原理两种情况，降水后土体总应力和有效应力增量计算值有差异，采用分层总和法计算了基于两种原理的沉降量。潜水含水土层沉降量计算偏差最大，基于总应力不变的沉降量比总应力可变的计算沉降量约大20%。本文计算原理对于抽取深层承压地下水导致地面沉降同样适用。
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| 关 键 词： | 地面沉降 有效应力增量 孔隙水压力 偏差值 |
| 文章编号： | 1003-8035(2001)01-0075-03 |
| 修稿时间： | 2000年6月26日 |
The calculation of
effective stress and settlement based on the variable total stress in pit dewatering |
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| Abstract: | To the question that the calculated settlement values is biggerthan practical values, the calculation of total stress and effective stress in confined and phreatic aquifers under different dewatering conditions is systematically analyzed in the paper. That the total stress in soil after dewatering is changeable, indicated in this paper. Especially in the unconfined layers that are mostly encountered in pit excavation, the total stress becomes little and the increment of effective stress is less than the decrease of pore water pressure. The calculation of total stress and effective stress based on the variable and constant principles is comparatively presented, and the settlement difference is shown applying the layerwise summation method with the practical example, the deviation of the calculated settlement resulting shows that the increment of the effective stress is not equal to decrease of the pore water pressure, the greatest deviation is in the phreatic aquifer, and up to 20%. The total stress variable principle is also applicable to the calculation of the settlement induced by drawing water in deep confined aquifers. |
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| Keywords: | settlement increment of effective stress pore water pressure deviation |
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