含水率对非饱和砂土似黏聚力影响试验研究
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摘要
目前工程上对待砂土地基时,都是将其作为完全无黏性土来对待;也就是将其黏聚力笼统的作为零。这种方式在理论研究中,简化了很多问题;但是在工程应用中,忽视似黏聚力的存在,有时候会带来诸多的不便,甚至是工程造价的翻番。为了研究非饱和砂土的似黏聚力,以工程实例"西咸能源金融大厦的基坑支护项目"为依托,选取了西咸新区,沣河以东,渭河以南交汇区域的砂土,进行了多组不同含水率、相同干密度的砂土的三轴、直剪以及基质吸力试验。试验结果表明:砂土的似黏聚力随着含水率的变化,呈现出由零先急速增长、然后增速放缓、再增速变大增长至峰值;并可以短暂维持峰值阶段,最后逐渐降低为零的结果。同时验证了砂土的直剪试验在工程上的可用性及安全性。其结论可以为非饱和土的研究提供参考。
At present,when treating sand foundations in engineering,they are treated as completely non-cohesive soil,that is,the cohesive force is generally zero. This method simplifies many problems in theoretical research,however,in engineering applications,ignoring the existence of cohesive force sometimes brings a lot of inconvenience,even the doubling of engineering cost. In order to study the cohesive force of unsaturated sand,the Xixian New Area was chosen,the east of the Weihe River and the sand of the south of the Weihe River,based on the engineering example "the foundation pit support project of Xixian energy finance building". Soil,three sets of triaxial,direct shear and matrix suction tests of sand with different water contents and the same dry density were carried out. The test results show that the clay-like cohesive force shows a rapid increase from zero first,then the growth rate slows down,then increases the speed to increase to the peak value,and can maintain the peak period for a short time,reduce the result to zero. At the same time,the availability and safety of the direct shear test of sand was verified. The conclusion can provide reference for the study of unsaturated soil.
At present,when treating sand foundations in engineering,they are treated as completely non-cohesive soil,that is,the cohesive force is generally zero. This method simplifies many problems in theoretical research,however,in engineering applications,ignoring the existence of cohesive force sometimes brings a lot of inconvenience,even the doubling of engineering cost. In order to study the cohesive force of unsaturated sand,the Xixian New Area was chosen,the east of the Weihe River and the sand of the south of the Weihe River,based on the engineering example "the foundation pit support project of Xixian energy finance building". Soil,three sets of triaxial,direct shear and matrix suction tests of sand with different water contents and the same dry density were carried out. The test results show that the clay-like cohesive force shows a rapid increase from zero first,then the growth rate slows down,then increases the speed to increase to the peak value,and can maintain the peak period for a short time,reduce the result to zero. At the same time,the availability and safety of the direct shear test of sand was verified. The conclusion can provide reference for the study of unsaturated soil.
引文
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10梁文鹏,吴家琦,谭晔,等.基于土水特征曲线的非饱和土强度预测[J].科学技术与工程,2018,18(4):333-338Liang Wenpeng,Wu Jiaqi,Tan Ye,et al.Shear strength prediction of unsaturated soil based on soil-water characteristic curve[J].Science Technology and Engineering,2018,18(4):333-338
11任传健,贾洪彪.非饱和土特性对朗肯土压力的影响[J].科学技术与工程,2015,15(25):78-82Ren Chuanjian,Jia Hongbiao.The influence of unsaturated soil’s characteristicson rankine earth pressure[J].Science Technology and Engineering,2015,15(25):78-82
2邢春艳,陆云瑜.含水量对非饱和土性质的影响[J].西部探矿工程,2007,19(10):35-37Xing Chunyan,Lu Yunyu.Influence of water content on the properties of unsaturated soil[J].Western Exploration Project,2007,19(10):35-37
3崔頔.非饱和砂土的表观黏聚力研究[J].北方交通,2014(2):86-87Cui Di.The research on apparent cohesion of unsaturation sand[J].Northern Traffic,2014(2):86-87
4董倩,侯龙,赵宝云.基质吸力对非饱和粉质砂土抗剪强度的影响[J].中南大学学报:自然科学版,2012,43(10):4017-4021Dong Qian,Hou Long,Zhao Baoyun.Effect of matrix suction on shear strength of unsaturated sandy soil[J].Journal of Central South University:Natural Science Edition,2012,43(10):4017-4021
5李业勋,刘文白,张辉.基于直剪试验的砂土细观力学性状研究[J].中国水运,2009,9(12):185-186Li Yexun,Liu Wenbai,Zhang Hui.Study on micromechanical properties of sand based on direct shear test[J].China Water Transport,2009,9(12):185-186
6李宣,孙德安.非饱和砂土和粉土的抗剪强度及其预测[J].工业建筑,2017,47(3):102-106Li Xuan,Sun Dean.Shear strength and prediction of unsaturated sand and silt[J].Industrial Building,2017,47(3):102-106
7李淑娥,金明东,陈志明等.海砂土三轴试验研究[J].山西建筑,2013,39(13):59-60Li Shue,Jing Mingdong,Chen Zhiming,et al.Triaxial test study on sea sandy soil[J].Shanxi Architecture,2013,39(13):59-60
8张平,殷洪建,吴昊.非饱和土砂土湿吸力[J].辽宁工程技术大学学报,2011,30(3):389-391Zhang Ping,Yin Hongjian,Wu Hao.Study on absorbed suction of unsaturated sandy soil[J].Journal of Liaoning Technical University,2011,30(3):389-391
9李建华,祝方才,陈春鸣,等.非饱和膨胀土抗剪强度的三轴试验研究[J].公路工程,2011,36(2):31-33Li Jianhua,Zhu Fangcai,Chen Chunming,et al.Experimental study of triaxial test of unsaturated expansive soil shear strength[J].Highway Engineering,2011,36(2):31-33
10梁文鹏,吴家琦,谭晔,等.基于土水特征曲线的非饱和土强度预测[J].科学技术与工程,2018,18(4):333-338Liang Wenpeng,Wu Jiaqi,Tan Ye,et al.Shear strength prediction of unsaturated soil based on soil-water characteristic curve[J].Science Technology and Engineering,2018,18(4):333-338
11任传健,贾洪彪.非饱和土特性对朗肯土压力的影响[J].科学技术与工程,2015,15(25):78-82Ren Chuanjian,Jia Hongbiao.The influence of unsaturated soil’s characteristicson rankine earth pressure[J].Science Technology and Engineering,2015,15(25):78-82