干湿循环对有无上覆荷载作用镇江下蜀土抗剪强度的影响
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摘要
针对下蜀土边坡常呈浅层滑动破坏的状况,选取镇江市某边坡的下蜀土为研究对象,通过干湿循环直剪试验,对制备试样时有、无上覆荷载,分别开展不同干湿循环次数下下蜀土抗剪强度劣化规律研究。结果表明:随着干湿循环次数的增加,无荷及有荷下蜀土的剪应力峰值、黏聚力及割线模量都逐渐降低,下蜀土黏聚力的衰减可用分段函数描述,当循环次数小于6时可用直线描述,而后趋近于一稳定值,而内摩擦角则保持相对稳定;法向应力及干湿循环次数相同,制样时有上覆荷载的下蜀土抗剪强度的衰减率明显小于无上覆荷载的衰减率,并且两种情况下的抗剪强度都随干湿循环次数的增加而不断衰减;相同干湿循环次数下,有上覆荷载下蜀土的黏聚力明显大于无上覆荷载的黏聚力,并且随着干湿循环次数的增加,其差距的增长率呈增大趋势。
As shallow landside used to occur in Xiashu soil slopes,Xiashu soil specimens of a slope in Zhenjiang were carry out direct shear test during wetting-drying cycles whether or not to be acted on by overburden load. The purpose was to obtain the degradation of shear strength of Xiashu soil during wetting-drying cycle. The test results indicated that peak shear stress,cohesion and secant modulus all decreased slowly with the increase number of wetting-drying cycles. The attenuation of cohesion of Xiashu soil could be described by piecewise function,and be described by a straight line when the frequency of wetting-drying cycles was less than 6,and then tended to a stable value,and the internal friction angle kept a steady state. The attenuation rate of shear strength for Xiashu soil being acted on by overburden load was obviously lower than that not to be acted on by overburded load under the same normal stress and wetting-drying cycle,and the shear strength decreased with increase of wetting-drying cycles in both cases. Under the same number of wetting-drying cycles,the cohesion of Xiashu soil being acted on by overburden load was obviously greater than that not to be acted on by overburded load. The difference between the two specimens increased with the increase of wetting-drying cycles.
As shallow landside used to occur in Xiashu soil slopes,Xiashu soil specimens of a slope in Zhenjiang were carry out direct shear test during wetting-drying cycles whether or not to be acted on by overburden load. The purpose was to obtain the degradation of shear strength of Xiashu soil during wetting-drying cycle. The test results indicated that peak shear stress,cohesion and secant modulus all decreased slowly with the increase number of wetting-drying cycles. The attenuation of cohesion of Xiashu soil could be described by piecewise function,and be described by a straight line when the frequency of wetting-drying cycles was less than 6,and then tended to a stable value,and the internal friction angle kept a steady state. The attenuation rate of shear strength for Xiashu soil being acted on by overburden load was obviously lower than that not to be acted on by overburded load under the same normal stress and wetting-drying cycle,and the shear strength decreased with increase of wetting-drying cycles in both cases. Under the same number of wetting-drying cycles,the cohesion of Xiashu soil being acted on by overburden load was obviously greater than that not to be acted on by overburded load. The difference between the two specimens increased with the increase of wetting-drying cycles.
引文
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[4]刘鹏,阎长虹,徐杨,等.南京地区下蜀土导热系数影响因素室内试验研究[J].防灾减灾工程学报,2016,36(5):847-852.
[5]杨和平,唐咸远,王兴正,等.有荷干湿循环条件下不同膨胀土抗剪强度基本特性[J].岩土力学,2018,39(7):2311-2317.
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[9]邓华锋,肖瑶,方景成,等.干湿循环作用下岸坡消落带土体抗剪强度劣化规律及其对岸坡稳定性影响研究[J].岩土力学,2017,38(9):2629-2638.
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[12]陈留凤,彭华.干湿循环对硬黏土的土水特性影响规律研究[J].岩石力学与工程学报,2016,35(11):2337-2344.
[13]中华人民共和国住房与城乡建设部.膨胀土地区建筑技术规范:GB 50112—2013[S].北京:中国建筑工业出版社,2012.
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[15]邓华锋,原先凡,李建林,等.土石混合体直剪试验的破坏特征及抗剪强度取值方法研究[J].岩石力学与工程学报,2013,32(增刊2):4065-4072.
[16]李维树,邬爱清,丁秀丽.三峡库区滑带土抗剪强度参数的影响因素研究[J].岩土力学,2006,27(1):56-60.
[17]刘顺青,洪宝宁,方庆军,等.高液限土和红黏土的水敏感性研究[J].深圳大学学报(理工版),2013,30(1):78-83.
[18]刘祖典,刘武农.非饱和土的强度特性[J].工程勘察,1999(1):7-9.
[19]李新明,孔令伟,郭爱国,等.基于工程包边法的膨胀土抗剪强度干湿循环效应试验研究[J].岩土力学,2014,35(3):675-682.
[20]杨和平,张锐,郑健龙.有荷条件下膨胀土的干湿胀缩变形及强度变化规律[J].岩土工程学报,2006,28(11):1936-1941.
[2]韩爱民,李彤,徐洪钟.脱湿状态下南京下蜀土的土水-力学特性[J].工程地质学报,2016,24(2):268-275.
[3]施威,魏继红,宋京雷,等.含水率对下蜀土抗剪强度的影响[J].西华大学学报(自然科学版),2016,35(3):97-101.
[4]刘鹏,阎长虹,徐杨,等.南京地区下蜀土导热系数影响因素室内试验研究[J].防灾减灾工程学报,2016,36(5):847-852.
[5]杨和平,唐咸远,王兴正,等.有荷干湿循环条件下不同膨胀土抗剪强度基本特性[J].岩土力学,2018,39(7):2311-2317.
[6]杨和平,王兴正,肖杰.干湿循环效应对南宁外环膨胀土抗剪强度的影响[J].岩土工程学报,2014,36(5):949-954.
[7]涂义亮,刘新荣,钟祖良,等.干湿循环下粉质黏土强度及变形特性试验研究[J].岩土力学,2017,38(12):3581-3589.
[8]袁志辉,倪万魁,唐春,等.干湿循环下黄土强度衰减与结构强度试验研究[J].岩土力学,2017,38(7):1894-1902.
[9]邓华锋,肖瑶,方景成,等.干湿循环作用下岸坡消落带土体抗剪强度劣化规律及其对岸坡稳定性影响研究[J].岩土力学,2017,38(9):2629-2638.
[10]穆坤,孔令伟,张先伟,等.红黏土工程性状的干湿循环效应试验研究[J].岩土力学,2016,37(8):2247-2253.
[11]查甫生,刘晶晶,许龙,等.水泥固化重金属污染土干湿循环特性试验研究[J].岩土工程学报,2013,35(7):1246-1252.
[12]陈留凤,彭华.干湿循环对硬黏土的土水特性影响规律研究[J].岩石力学与工程学报,2016,35(11):2337-2344.
[13]中华人民共和国住房与城乡建设部.膨胀土地区建筑技术规范:GB 50112—2013[S].北京:中国建筑工业出版社,2012.
[14]中华人民共和国住房与城乡建设部.土工试样方法标准:GB/T 50123—1999[S].北京:中国计划出版社,1999.
[15]邓华锋,原先凡,李建林,等.土石混合体直剪试验的破坏特征及抗剪强度取值方法研究[J].岩石力学与工程学报,2013,32(增刊2):4065-4072.
[16]李维树,邬爱清,丁秀丽.三峡库区滑带土抗剪强度参数的影响因素研究[J].岩土力学,2006,27(1):56-60.
[17]刘顺青,洪宝宁,方庆军,等.高液限土和红黏土的水敏感性研究[J].深圳大学学报(理工版),2013,30(1):78-83.
[18]刘祖典,刘武农.非饱和土的强度特性[J].工程勘察,1999(1):7-9.
[19]李新明,孔令伟,郭爱国,等.基于工程包边法的膨胀土抗剪强度干湿循环效应试验研究[J].岩土力学,2014,35(3):675-682.
[20]杨和平,张锐,郑健龙.有荷条件下膨胀土的干湿胀缩变形及强度变化规律[J].岩土工程学报,2006,28(11):1936-1941.
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