工程地质学报
工程地質學報
공정지질학보
2014年
5期
890-895
,共6页
杨璠%常维%汪发武%李同录
楊璠%常維%汪髮武%李同錄
양번%상유%왕발무%리동록
黄土%高速远程滑坡%运动模拟%孔隙水压力
黃土%高速遠程滑坡%運動模擬%孔隙水壓力
황토%고속원정활파%운동모의%공극수압력
Loess%Rapid long run-out slide%Motion simulation%Pore water pressure
陕西泾阳南塬的东风滑坡是一个典型的高速远程黄土滑坡,由于斜坡顶部的黄土台塬长期灌溉所诱发。通过野外调查,采取滑坡后缘斜坡的黄土试样,对斜坡中部的Q2黄土做天然含水率的固结不排水剪试验,对斜坡底部地下水位面附近的Q1黄土做饱和固结不排水剪试验,结果表明非饱和的Q2黄土和饱和的Q1黄土在破坏后都具有显著的应力降,但前者是由结构强度引起,而后者则是由剪切形成的超孔隙水压力引起,由此表明该斜坡一旦破坏,就会有较高的启动速度。对滑坡坡脚以外一级阶地上的砂卵层做环剪慢剪试验,测得其有效残余摩擦角,根据滑坡各部分含水状态给定孔隙水压力参数,利用Sassa.K滑坡运动模型对该滑坡运动过程进行模拟,从模拟结果反映出滑坡运动过程中的覆盖范围和速度的变化,模拟的滑坡运动距离和覆盖范围与实测比较吻合,最高速可达到37m·s-1,为高速滑坡。黄土滑坡以高的初速度下滑到坡脚下一级阶地上的饱和砂卵层上,砂卵层上液化是导致其远程运动的主要原因。
陝西涇暘南塬的東風滑坡是一箇典型的高速遠程黃土滑坡,由于斜坡頂部的黃土檯塬長期灌溉所誘髮。通過野外調查,採取滑坡後緣斜坡的黃土試樣,對斜坡中部的Q2黃土做天然含水率的固結不排水剪試驗,對斜坡底部地下水位麵附近的Q1黃土做飽和固結不排水剪試驗,結果錶明非飽和的Q2黃土和飽和的Q1黃土在破壞後都具有顯著的應力降,但前者是由結構彊度引起,而後者則是由剪切形成的超孔隙水壓力引起,由此錶明該斜坡一旦破壞,就會有較高的啟動速度。對滑坡坡腳以外一級階地上的砂卵層做環剪慢剪試驗,測得其有效殘餘摩抆角,根據滑坡各部分含水狀態給定孔隙水壓力參數,利用Sassa.K滑坡運動模型對該滑坡運動過程進行模擬,從模擬結果反映齣滑坡運動過程中的覆蓋範圍和速度的變化,模擬的滑坡運動距離和覆蓋範圍與實測比較吻閤,最高速可達到37m·s-1,為高速滑坡。黃土滑坡以高的初速度下滑到坡腳下一級階地上的飽和砂卵層上,砂卵層上液化是導緻其遠程運動的主要原因。
협서경양남원적동풍활파시일개전형적고속원정황토활파,유우사파정부적황토태원장기관개소유발。통과야외조사,채취활파후연사파적황토시양,대사파중부적Q2황토주천연함수솔적고결불배수전시험,대사파저부지하수위면부근적Q1황토주포화고결불배수전시험,결과표명비포화적Q2황토화포화적Q1황토재파배후도구유현저적응력강,단전자시유결구강도인기,이후자칙시유전절형성적초공극수압력인기,유차표명해사파일단파배,취회유교고적계동속도。대활파파각이외일급계지상적사란층주배전만전시험,측득기유효잔여마찰각,근거활파각부분함수상태급정공극수압력삼수,이용Sassa.K활파운동모형대해활파운동과정진행모의,종모의결과반영출활파운동과정중적복개범위화속도적변화,모의적활파운동거리화복개범위여실측비교문합,최고속가체도37m·s-1,위고속활파。황토활파이고적초속도하활도파각하일급계지상적포화사란층상,사란층상액화시도치기원정운동적주요원인。
The Dongfeng loess landslide on the south platform in Jing Yang is a typical type of high-speed long distant landslides,induced by the long-term irrigation at the top tableland of the slope.After field investigation, loess samples are taken in different parts of the slope.The intact samples taken in the central slope(Q2)are utilized to do the CU tests,and the ones taken in the slope bottom (Q1 )are saturated and then used to conduct the CU tests.Results show that both the unsaturated loess Q2 and the saturated loess Q1 display significantly stress decrease. However,they have different reasons.For the former is caused by the decline of structure strength,while the latter is caused by the pore water pressure generated during the shearing process.All above reveal that once the slope failure occurs,there will be high initiating speed.The ring shear tests are conducted on the sand on the first terrace out of the slope toe to obtain the effective residual friction angle.Then according to the situation of water contents, pore pressure coefficients in different parts are obtained.Then the landslide movement process can be simulated by Sassa's landslide motion model,which can show the speed changes and the coverage of landslide.The simulation results are in good agreement with the measures results.The highest speed can reach 37m·s-1 ,also revealing that it is a high speed landslide.The loess landslide with high initial velocity down to the slope foot in the saturate sand layer of the first terraces and liquefaction in the sand layer is the main factor of its remote movement.