CAJ | 학술논문

为了解河南南阳地区膨胀土渠道边坡滑坡机制，基于南水北调中线工程南阳段19个滑坡的现场调研统计结果，选取南阳段 TS105+400处右岸滑坡为典型实例，开挖探槽揭露滑坡内部结构，对该区膨胀土渠道滑坡的破坏特征及演化机制进行了研究。结果显示，该区滑坡多发生在 al+pl2Q 地层；边坡的稳定性受中上部土体中的垂直节理及坡脚充填强膨胀土的缓倾长大裂隙共同控制，滑动面由后缘陡倾裂隙及前缘缓倾长大裂隙组成。开挖卸荷导致垂直节理张开，垂直节理向下可延伸3m以上，破坏边坡土体整体性，且充当水分出入边坡的主要通道；坡面以下深度4～8m存在一个高湿度带，带内土体强度小，发育滑动面。气候造成的胀缩循环、开挖卸荷导致边坡垂直节理张开并向深部发展，对边坡土体的强度衰减作用明显，当垂直裂隙与前缘缓倾裂隙贯通后，发生强（久）降雨，裂隙充水软化，即诱发边坡失稳。
위료해하남남양지구팽창토거도변파활파궤제，기우남수북조중선공정남양단19개활파적현장조연통계결과，선취남양단 TS105+400처우안활파위전형실례，개알탐조게로활파내부결구，대해구팽창토거도활파적파배특정급연화궤제진행료연구。결과현시，해구활파다발생재 al+pl2Q 지층；변파적은정성수중상부토체중적수직절리급파각충전강팽창토적완경장대렬극공동공제，활동면유후연두경렬극급전연완경장대렬극조성。개알사하도치수직절리장개，수직절리향하가연신3m이상，파배변파토체정체성，차충당수분출입변파적주요통도；파면이하심도4～8m존재일개고습도대，대내토체강도소，발육활동면。기후조성적창축순배、개알사하도치변파수직절리장개병향심부발전，대변파토체적강도쇠감작용명현，당수직렬극여전연완경렬극관통후，발생강（구）강우，렬극충수연화，즉유발변파실은。
In order to understand the mechanism of expansive soil canal slope slide, a study is conducted based on the statistical results of 19 landslides at the Nanyang Section of Middle Route of South-to-North Water Transfer Project. The right bank landslide at TS105+400 is selected as typical landslide. Excavating trench exposes internal structure of landslide. A series of geological survey has been done to study the characteristics and evolution mechanism of expansive soil landslide in the area by excavating trench slides. The results show that, most landslides in the area occurred in the al+pl2Q strata. Slope stability is jointly controlled by vertical joints in the upper layer soil and the gently dipping big fissures at the toe of the slope, which are filled with highly expansive clay. Sliding surface is composed of the steep tilting cracks at the trailing edge of slope and big gently dipping fractures at the toe of slope. Excavation unloading effect causes the vertical joints’ opening. These joints can extend more than 3 meters into the slope, which destroys the integrity of the slope soil and serves as the main channel for water to go in and out of the slope;there is a high humidity area 4 to 8 meters below the surface of slope. Soil within the area is weak and the sliding surface develops in it. Wetting and drying cycles caused by climate and excavation unloading lead to the vertical crack to open and propagation deep into slope. This effect causes a dramatic attenuation of soil strength. The vertical cracks connected with the big gently dipping fissures at the toe of the slope eventually. The slope slides after these fissure and crack are filled with water after the occurrence of strong lasting precipitation.