崩岗侵蚀区非饱和花岗岩残积土强度特性试验研究
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摘要
以崩岗侵蚀区花岗岩残积土为研究对象,应用非饱和土三轴仪对重塑花岗岩残积土进行强度特性试验,研究干密度、净围压和基质吸力对应力-应变关系和强度的影响规律,并分析重塑非饱和花岗岩残积土在控制吸力条件下的抗剪强度特性。结果表明,非饱和花岗岩残积土的应力-应变关系均呈硬化型;在干密度相同时,非饱和土强度随着基质吸力和净围压的增大而增大;在净围压相同条件下,非饱和土强度随着基质吸力和干密度的增大而增大;基质吸力对粘聚力影响较大,基本上呈线性增长关系,而有效内摩擦角受基质吸力的影响较小,几乎可以不计;非饱和重塑花岗岩残积土的强度随着基质吸力和干密度增大而增大,与基质吸力相关的摩擦角较大。
The strength characteristics of unsaturated granite residual soil in collapsing erosion area are investigated by a series of triaxial tests with suction-controlled conditions. The influences of different initial dry density,net confining pressure and suction on stress-strain relationship and strength of unsaturated residual soils are studied and the shear strength characteristics of remolded unsaturated granite residual soil under suction-controlled conditions are analyzed. The results show that,( a) the stress-strain relationship of unsaturated granite residual soil exhibits a characteristics of strain-hardening;( b) under the condition of same dry density,the peak strength increases with the increase of suction and net confining pressure;( c) under same net confining pressure,the peak strength increases with the increase of suction and dry density;( d) the cohesion increases greatly with the increasing of suction with a linear growth to suction,but the suction has smaller effect on friction angle which can be nearly ignored; and( e) the increases of suction and dry densities have a positive effect on the strength of residual soil,and the triaxial shear coefficient is larger.
The strength characteristics of unsaturated granite residual soil in collapsing erosion area are investigated by a series of triaxial tests with suction-controlled conditions. The influences of different initial dry density,net confining pressure and suction on stress-strain relationship and strength of unsaturated residual soils are studied and the shear strength characteristics of remolded unsaturated granite residual soil under suction-controlled conditions are analyzed. The results show that,( a) the stress-strain relationship of unsaturated granite residual soil exhibits a characteristics of strain-hardening;( b) under the condition of same dry density,the peak strength increases with the increase of suction and net confining pressure;( c) under same net confining pressure,the peak strength increases with the increase of suction and dry density;( d) the cohesion increases greatly with the increasing of suction with a linear growth to suction,but the suction has smaller effect on friction angle which can be nearly ignored; and( e) the increases of suction and dry densities have a positive effect on the strength of residual soil,and the triaxial shear coefficient is larger.
引文
[1]吴志峰,王继增.华南花岗岩风化壳岩土特性与崩岗侵蚀关系[J].水土保持学报,2000,14(2):31-35.
[2]颜波,汤连生,胡辉,等.花岗岩风化土崩岗破坏机理分析[J].水文地质工程地质,2009(6):68-71.
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[7]林金石,庄雅婷,黄炎和,等.不同剪切方式下崩岗红土层抗剪特征随水分变化规律[J].农业工程学报,2015,31(24):106-110.
[8]孔令伟,周葆春,白颢,等.荆门非饱和膨胀土的变形与强度特性试验研究[J]. 2010,31(10):3036-3042.
[9]马秀婷,邵生俊,杨春鸣,等.非饱和结构性黄土的强度特性试验研究[J],岩土工程学报,2013,35(Z1):68-75.
[10] KIM B S,SHIBUYA S,PARK S W,et al. Application of suction stress for estimating unsaturated shear strength of soils using direct shear testing under low confining pressure[J]. Canadian Geotechnical Journal,2010,47(9):955-970.
[11]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性[J].岩土工程学报,2011,33(6):901-908.
[12]张抒,唐辉明.非饱和花岗岩残积土崩解机制试验研究[J].岩土力学,2013,34(6):1668-1674.
[13]周小文,刘攀,胡黎明,等.结构性花岗岩残积土的剪切屈服特性试验研究[J].岩土力学,2015,36(Z2):157-163
[14]邓羽松,丁树文,蔡崇法,等.鄂东南崩岗剖面土壤水分特征曲线及模拟[J].土壤学报,2016,53(2):355-364.
[15]吴俊杰,王成华,李广信.非饱和土基质吸力对边坡稳定的影响[J].岩土力学,2004,25(5):732-736.
[16]陈正汉,孙树国,方祥位,等.非饱和土与特殊土测试技术新进展[J].岩土工程学报,2006,28(2):147-169.
[17] FREDLUND D G,MORGENSTERN N R,WIDGER R A. The shear strength of unsaturated soils[J]. Canadian Geotechnical Journal,1978,15(3):313-321.
[18]韩华强,陈生水,郑澄锋.非饱和膨胀土强度及变形特性试验研究[J].岩土工程学报,2008,30(12):1872-1876.
[19] MATSUSHI Y,MATSUKURA Y. Cohesion of unsaturated residual soils as a function of volumetric water content[J]. Bulletin of Engineering Geology and the Environment,2006,65(4):449-455.
[2]颜波,汤连生,胡辉,等.花岗岩风化土崩岗破坏机理分析[J].水文地质工程地质,2009(6):68-71.
[3]陈晓安,杨洁,熊永,等.红壤区崩岗侵蚀的土壤特性与影响因素研究[J].水利学报,2013,44(10):1175-1181.
[4]陈晓安.崩岗侵蚀区土壤物理性质分层差异及其对崩岗发育的影响[J].中国水土保持,2015(12):71-72.
[5]张晓明,丁树文,蔡崇法.干湿效应下崩岗区岩土抗剪强度衰减非线性分析[J].农业工程学报,2012,28(5):241-245.
[6]林敬兰,黄炎和,张德斌,等.水分对崩岗土体抗剪切特性的影响[J].水土保持学报,2013,27(3):55-58.
[7]林金石,庄雅婷,黄炎和,等.不同剪切方式下崩岗红土层抗剪特征随水分变化规律[J].农业工程学报,2015,31(24):106-110.
[8]孔令伟,周葆春,白颢,等.荆门非饱和膨胀土的变形与强度特性试验研究[J]. 2010,31(10):3036-3042.
[9]马秀婷,邵生俊,杨春鸣,等.非饱和结构性黄土的强度特性试验研究[J],岩土工程学报,2013,35(Z1):68-75.
[10] KIM B S,SHIBUYA S,PARK S W,et al. Application of suction stress for estimating unsaturated shear strength of soils using direct shear testing under low confining pressure[J]. Canadian Geotechnical Journal,2010,47(9):955-970.
[11]陈晓平,周秋娟,蔡晓英.高液限花岗岩残积土的物理特性和剪切特性[J].岩土工程学报,2011,33(6):901-908.
[12]张抒,唐辉明.非饱和花岗岩残积土崩解机制试验研究[J].岩土力学,2013,34(6):1668-1674.
[13]周小文,刘攀,胡黎明,等.结构性花岗岩残积土的剪切屈服特性试验研究[J].岩土力学,2015,36(Z2):157-163
[14]邓羽松,丁树文,蔡崇法,等.鄂东南崩岗剖面土壤水分特征曲线及模拟[J].土壤学报,2016,53(2):355-364.
[15]吴俊杰,王成华,李广信.非饱和土基质吸力对边坡稳定的影响[J].岩土力学,2004,25(5):732-736.
[16]陈正汉,孙树国,方祥位,等.非饱和土与特殊土测试技术新进展[J].岩土工程学报,2006,28(2):147-169.
[17] FREDLUND D G,MORGENSTERN N R,WIDGER R A. The shear strength of unsaturated soils[J]. Canadian Geotechnical Journal,1978,15(3):313-321.
[18]韩华强,陈生水,郑澄锋.非饱和膨胀土强度及变形特性试验研究[J].岩土工程学报,2008,30(12):1872-1876.
[19] MATSUSHI Y,MATSUKURA Y. Cohesion of unsaturated residual soils as a function of volumetric water content[J]. Bulletin of Engineering Geology and the Environment,2006,65(4):449-455.