考虑消落带土体强度弱化的库区涉水边坡稳定性研究
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摘要
三峡库区涉水土质边坡在长期的库水位涨落条件下,消落带土体长期处于周期性的饱和-干燥-饱和过程,对边坡的稳定性不利。以某滑坡消落带土体为研究对象,以干湿循环作用过程模拟消落带土体环境,对完成干湿循环作用后的试样进行直剪试验,得到试样参数在水作用下的弱化程度,在此基础上采用Geo-slope软件对滑坡的稳定性进行分析。试验结果表明,土体的黏聚力c和摩擦角φ随着干湿循环作用次数n的增加均呈指数型降低趋势,拟合度达0.99以上;土体弱化程度随干湿循环作用次数n的增加非线性增大;周期性干湿循环作用主要通过水分的渗入与渗出造成土体强度的弱化。将滑坡岩土体分为自然条件影响区域、干湿循环作用区域及浸泡饱和区域,依据试验结果对干湿循环作用区域土体强度参数进行折减,并进行数值计算,结果表明,滑坡体安全系数F随着干湿循环作用次数n的增加呈指数型降低趋势,滑坡体由基本稳定状态向欠稳定状态发展,直至边坡失稳。
Under the condition of long-term fluctuation of reservoir water level,the soil and rockmass in the fluctuation zone is in the periodic saturation and drying process,which is harmful to the stability of the slope. This paper simulates the water level fluctuation environment of the soil and rockmass in the fluctuation zone with the process of dry-wet cycle,and the direct shear test is conducted with the soil of a landslide fluctuation zone,and the stability of the landslide with Geo-slope software is analyzed. The experimental results indicate that the cohesion force c and the friction angle φ decrease exponentially with the increase in dry-wet cycles n,with a fitting degree of more than 0.99; the weakening degree of the soil has a non-linear increasing trend with the increase in the dry-wet cycle n. The soil strength is weakened by the infiltration and exudation of water in the dry-wet cycle process. The landslide regional is divided into three parts: natural conditions area,dry-wet cycle area and soaked saturation area,and the numerical simulation is performed based on the soil strength results of dry-wet cycles. The results show that the safety coefficient F of the landslide decreases exponentially with the increasing dry-wet cycle n.The stability of the landslide changes from the basic stable state to the under steady state,until the landslide becomes unstable.
Under the condition of long-term fluctuation of reservoir water level,the soil and rockmass in the fluctuation zone is in the periodic saturation and drying process,which is harmful to the stability of the slope. This paper simulates the water level fluctuation environment of the soil and rockmass in the fluctuation zone with the process of dry-wet cycle,and the direct shear test is conducted with the soil of a landslide fluctuation zone,and the stability of the landslide with Geo-slope software is analyzed. The experimental results indicate that the cohesion force c and the friction angle φ decrease exponentially with the increase in dry-wet cycles n,with a fitting degree of more than 0.99; the weakening degree of the soil has a non-linear increasing trend with the increase in the dry-wet cycle n. The soil strength is weakened by the infiltration and exudation of water in the dry-wet cycle process. The landslide regional is divided into three parts: natural conditions area,dry-wet cycle area and soaked saturation area,and the numerical simulation is performed based on the soil strength results of dry-wet cycles. The results show that the safety coefficient F of the landslide decreases exponentially with the increasing dry-wet cycle n.The stability of the landslide changes from the basic stable state to the under steady state,until the landslide becomes unstable.
引文
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[14]刘新荣,李栋梁,张梁,等.干湿循环对泥质砂岩力学特性及其微细观结构影响研究[J].岩土工程学报,2016,38(7):1 291-1 300.
[15]姜永东,阎宗岭,刘元雪,等.干湿循环作用下岩石力学性质的实验研究[J].中国矿业,2011,20(5):104-106,110.
[16] Mario Camilo Torres-Suarez,Adolfo Alarcon-Guzman,Rafael Berdugo-De Moya. Effectsof loading-unloading and wetting-drying cycles on geomechanical behaviors of mudrocks in the Colombian Andes[J]. Journal of Rock Mechanics andGeotechnical Engineering,2014,6:257-268.
[17] Maximiliano R Vergara,Theodoros Triantafyllidis. Swelling behavior of volcanic rocksunder cyclic wetting and drying[J]. International Journal of Rock Mechanics&MiningS ciences,2015,80:231-240.
[18]江强强,刘路路,焦玉勇,等.干湿循环下滑带土强度特性与微观结构[J].岩土力学,2019,40:1-9.
[19]董金玉,赵志强,杨继红,等.干湿循环作用下滑带土的变形演化和强度参数弱化试验研究[J].四川大学学报(工程科学版),2016,48(S2):1-7.
[2]高连通,易夏玮,李喜,等.三峡库区典型滑坡变形与高水位涨落关系研究[J].地质科技情报,2011,30(4):132-136.
[3]邓合玉,陈勇.库水升降条件下滑坡变形失稳机理研究[J].三峡大学学报(自然科学版),2018,40(6):30-34.
[4]赵瑞欣,殷跃平,李滨,等.库水波动下堆积层滑坡稳定性研究[J].水利学报,2017,48(4):435-445.
[5]严飞,文海,邓琴,等.库水对香丽金沙江大桥丽江岸边坡稳定性影响[J].中国农村水利水电,2017(6):134-137.
[6]陈洪凯,周晓涵,谭玲.降雨特性对滑坡孔隙水压力影响的试验研究[J].重庆师范大学学报(自然科学版),2017,34(1):49-54.
[7]向云龙,符文熹,周洪福.考虑地表径流拖曳力效应多层边坡稳定性分析[J].中国农村水利水电,2018(6):145-150,156.
[8]黄强,程勇刚,周伟,等.降雨入渗下非饱和土质边坡稳定性的最小势能法研究[J].中国农村水利水电,2018(1):154-160,164.
[9]周永强,盛谦.库水位变化和降雨作用下付家坪子高陡滑坡稳定性研究[J].长江科学院院报,2014,31(2):57-61,67.
[10]韩金明,肖明.考虑降雨特征的浅层边坡稳定性分析[J].中国农村水利水电,2011(5):105-108,112.
[11]卢书强,张国栋,易庆林,等.三峡库区白家包阶跃型滑坡动态变形特征与机理[J].南水北调与水利科技,2016,14(3):144-149.
[12]汤罗圣,殷坤龙.基于R/S分析方法的渐进式滑坡位移预测研究[J].水文地质工程地质,2013,40(3):93-97.
[13]易庆林,曾怀恩,黄海峰.利用BP神经网络进行水库滑坡变形预测[J].水文地质工程地质,2013,40(1):124-128.
[14]刘新荣,李栋梁,张梁,等.干湿循环对泥质砂岩力学特性及其微细观结构影响研究[J].岩土工程学报,2016,38(7):1 291-1 300.
[15]姜永东,阎宗岭,刘元雪,等.干湿循环作用下岩石力学性质的实验研究[J].中国矿业,2011,20(5):104-106,110.
[16] Mario Camilo Torres-Suarez,Adolfo Alarcon-Guzman,Rafael Berdugo-De Moya. Effectsof loading-unloading and wetting-drying cycles on geomechanical behaviors of mudrocks in the Colombian Andes[J]. Journal of Rock Mechanics andGeotechnical Engineering,2014,6:257-268.
[17] Maximiliano R Vergara,Theodoros Triantafyllidis. Swelling behavior of volcanic rocksunder cyclic wetting and drying[J]. International Journal of Rock Mechanics&MiningS ciences,2015,80:231-240.
[18]江强强,刘路路,焦玉勇,等.干湿循环下滑带土强度特性与微观结构[J].岩土力学,2019,40:1-9.
[19]董金玉,赵志强,杨继红,等.干湿循环作用下滑带土的变形演化和强度参数弱化试验研究[J].四川大学学报(工程科学版),2016,48(S2):1-7.