厦门花岗岩风化层的地震扁铲侧胀(SDMT)试验研究
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摘要
花岗岩风化土属于一种区域性特殊土,易扰动,其力学指标的确定多采用原位测试手段。通过对厦门地铁轨道交通1号线3个站点的典型花岗岩风化层开展地震扁铲侧胀试验,系统评价该类土的原位力学特性。结果表明,厦门花岗岩残积土土质分类为粉土-砂性土,具有似超固结特性,计算OCR值普遍大于1,排水特性属于部分排水类型;花岗岩残积土的力学性质指标对风化程度特别敏感,随埋深增加,风化程度逐渐减弱,土质分类由粉土向砂性土转化,土体水平应力减小,强度与刚度增加,剪切波速值逐渐增大,似超固结特性逐渐减弱,排水特性逐渐从非排水型向排水型过渡;利用剪切波速和土类指数ID可以较好地对花岗岩风化土进行土质分类。地震扁铲侧胀试验(SDMT)作为一种新型改进原位测试手段,试验结果能较好反映花岗岩风化层物理力学性能,具有一定的可靠性与较广泛的适用性。论文研究结果对厦门地区花岗岩风化土地基的优化设计具有直接的指导与借鉴意义。
Weathered granite in Xiamen is a kind of regional special soil. Its mechanical index is usually investigated with in-situ test because of disturbance. The in-situ mechanical properties of the weathered soils are evaluated by seismic dilatometer test of typical weathering granite layer at three sites of Xiamen Metro Line 1. The results show that the weathered soil derived from granite in Xiamen is classified as silty-sandy soil with quasioverconsolidation characteristics. Its OCR values are generally larger than 1. It belongs to a part drainage type.Mechanical behavior of the weathered soil particularly is sensitive to the degree of weathering. As burial depth increases,the degree of weathering is gradually weakened. This will cause the horizontal stress of soil decreases,while the strength,rigidity and the shear wave velocity of soil increase. Furthermore,the soil classification is transformed from silt to sandy soil,the quasi-overconsolidation characteristics are weakened and the drainage characteristics is translated from the non-drainage type to the drainage type. Therefore,the seismic dilatometer test is especially suitable for weathered granite stratum with the good reliability and wide applicability. The study has direct guidance for the optimization design of the weathered soil foundation in Xiamen.
Weathered granite in Xiamen is a kind of regional special soil. Its mechanical index is usually investigated with in-situ test because of disturbance. The in-situ mechanical properties of the weathered soils are evaluated by seismic dilatometer test of typical weathering granite layer at three sites of Xiamen Metro Line 1. The results show that the weathered soil derived from granite in Xiamen is classified as silty-sandy soil with quasioverconsolidation characteristics. Its OCR values are generally larger than 1. It belongs to a part drainage type.Mechanical behavior of the weathered soil particularly is sensitive to the degree of weathering. As burial depth increases,the degree of weathering is gradually weakened. This will cause the horizontal stress of soil decreases,while the strength,rigidity and the shear wave velocity of soil increase. Furthermore,the soil classification is transformed from silt to sandy soil,the quasi-overconsolidation characteristics are weakened and the drainage characteristics is translated from the non-drainage type to the drainage type. Therefore,the seismic dilatometer test is especially suitable for weathered granite stratum with the good reliability and wide applicability. The study has direct guidance for the optimization design of the weathered soil foundation in Xiamen.
引文
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Zhang X W,Kong L W,Chen C,et al.2016a.Experimental investigation on relative contribution of hot and humid weather and heavy rainfall in disintegration of basalt residual soil[J].Scientia Sinica Technologica,46(11):1175-1184.
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Zhang X W,Li J J,Li J,et al.2014.Structure and composition of residual soil from decomposed basalt at Leizhou peninsula[J].Journal of Engineering Geology,22(5):797-803.
福建省建设厅.2006.岩土工程勘察规范(DBJ 13-84-2006)[S].福州:福建省科学技术出版社.
简文彬,胡海瑞,罗阳华,等.2017.干湿循环下花岗岩残积土强度衰减试验研究[J].工程地质学报,25(3):592-597.
尹松,孔令伟,张先伟.2017.炎热多雨气候影响下残积土小应变刚度特性试验研究[J].岩土工程学报,39(4):743-751.
张抒,唐辉明.2013.非饱和花岗岩残积土崩解机制试验研究[J].岩土力学,34(6):1668-1674.
张先伟,孔令伟,陈成,等.2016a.炎热多雨和突降暴雨气候影响下玄武岩残积土的崩解试验研究[J].中国科学:技术科学,46(11):1175-1184.
张先伟,李仁耿,郑永民,等.2016b.顺德强风化岩层预应力管桩桩端土软化的现场试验研究[J].中国科学:技术科学,46(9):975-986.
张先伟,李晶晶,李峻,等.2014.雷州半岛玄武岩残积土的物质成分与结构特征[J].工程地质学报,22(5):797-803.
Housing and Urban-Rural Development of Fujian.2006.Code for investigation of geotechnical engineering(DBJ 13-84-2006)[S].Fuzhou:Fujian Science and Technology Publishing House.
Jian W B,Hu H R,Luo Y H,et al.2017.Experimental study on deterioration of granitic residual soil strength in wetting-drying cycles[J].Journal of Engineering Geology,25(3):592-597.
Kim C K,Kim T H.2010.Behavior of unsaturated weathered residual granite soil with initial watercontents[J].Engineering Geology,113(1-4):1-10.
Marchetti S.1980.In situ tests by flat dilatometer[J].Journal of the Geotechnical Engineering Division,106(3):299-321.
Monaco P,Amoroso S,Marchetti S,et al.2014.Overconsolidation and stiffness of venice lagoon sands and silts from SDMT and CPTU[J].Journal of Geotechnical and Geoenvironmental Engineering,140(1):215-227.
Schnaid F,Odebrecht E,Sosnoski J,et al.2016.Effects of test procedure on flat dilatometer test(DMT)results in intermediate soils[J].Canadian Geotechnical Journal,53(8):1270-1280.
Yin S,Kong L W,Zhang X W.2017.Experimental study on stiffness characteristics of residual soil at small strain under hot and rainy climate[J].Chinese Journal of Geotechnical Engineering,39(4):743-751.
Zhang S,Tang H M.2013.Experimental study of disintegration mechanism for unsaturated granite residual soil[J].Rock and Soil Mechanics,34(6):1668-1674.
Zhang X W,Kong L W,Chen C,et al.2016a.Experimental investigation on relative contribution of hot and humid weather and heavy rainfall in disintegration of basalt residual soil[J].Scientia Sinica Technologica,46(11):1175-1184.
Zhang X W,Li R G,Zheng Y M,et al.2016b.Field experimental study on prestressed concrete tube-pile bearing stratum softening in strong weathered rock formation of Shunde area[J].Scientia Sinica Technologica,46(9):975-986.
Zhang X W,Kong L W,Yin S,et al.2017.Engineering geology of basalt residual soil in Leiqiong,southern China[J].Engineering Geology,220:196-207.
Zhang X W,Li J J,Li J,et al.2014.Structure and composition of residual soil from decomposed basalt at Leizhou peninsula[J].Journal of Engineering Geology,22(5):797-803.
福建省建设厅.2006.岩土工程勘察规范(DBJ 13-84-2006)[S].福州:福建省科学技术出版社.
简文彬,胡海瑞,罗阳华,等.2017.干湿循环下花岗岩残积土强度衰减试验研究[J].工程地质学报,25(3):592-597.
尹松,孔令伟,张先伟.2017.炎热多雨气候影响下残积土小应变刚度特性试验研究[J].岩土工程学报,39(4):743-751.
张抒,唐辉明.2013.非饱和花岗岩残积土崩解机制试验研究[J].岩土力学,34(6):1668-1674.
张先伟,孔令伟,陈成,等.2016a.炎热多雨和突降暴雨气候影响下玄武岩残积土的崩解试验研究[J].中国科学:技术科学,46(11):1175-1184.
张先伟,李仁耿,郑永民,等.2016b.顺德强风化岩层预应力管桩桩端土软化的现场试验研究[J].中国科学:技术科学,46(9):975-986.
张先伟,李晶晶,李峻,等.2014.雷州半岛玄武岩残积土的物质成分与结构特征[J].工程地质学报,22(5):797-803.