摘要
为探明膨胀土边坡受到降雨影响的稳定性变化特征,以广西宁明盆地某省道旁膨胀土边坡为背景,在前期室内试验的基础上,采用数值模拟研究了开挖削坡前后不同降雨强度对边坡稳定性的影响,最后根据膨胀土边坡特性,提出膨胀土边坡生态防护和监测措施。结果显示,边坡膨胀黏土层饱和前后重度、内聚力及内摩擦角均有较大变化,对边坡稳定有较大影响,膨胀率测定显示,该膨胀土层属弱膨胀土。降雨作用对开挖前边坡稳定性影响较大,未开挖前天然状态边坡安全系数为1.326,一旦受到降雨影响,边坡安全系数骤降至1.077左右,边坡处于基本稳定状态。当边坡土体全部达到饱和状态时,边坡安全系数降至1.032,边坡处于欠稳定状态。经过边坡局部开挖削坡并压实后,边坡整体稳定性得到提升,在天然状态下安全系数达到2.078,在降雨作用和饱和状态下,边坡安全系数分别为1.48左右和1.379,边坡整体仍然处于稳定状态,碾压后的边坡受到内部水的影响减小。通过采用铁丝网+多年生黑麦草和狗牙根间隔种植的生态防护措施,可保证边坡的整体稳定性并便于变形控制。
To investigate the stability changes of expansive soil slopes under rainfall influence,this study takes an expansive soil slope adjacent to a provincial highway in the Ningming Basin,Guangxi,as the background.Based on preliminary laboratory tests,numerical simulations were conducted to analyze the effects of different rainfall intensities on slope stability before and after excavation and slope cutting.Finally,ecological protection and monitoring measures for expansive soil slopes were proposed according to their characteristics.The results indicate significant changes in the unit weight,cohesion,and internal friction angle of the expansive clay layer before and after saturation,which greatly impact slope stability.Expansivity measurements classify this expansive soil layer as weakly expansive.Rainfall significantly affects the stability of pre-excavation slopes:the natural state safety factor of the unexcavated slope is 1.326,which drops sharply to approximately 1.077 under rainfall influence,placing the slope in a basically stable state.When the slope soil reaches full saturation,the safety factor decreases to 1.032,entering an understable state.After partial excavation,slope cutting,and compaction,the overall slope stability improves:the safety factor reaches 2.078 under natural conditions,1.48 under rainfall,and 1.379 under saturation,maintaining overall stability.The compacted slope reduces internal water influence.Ecological protection measures combining wire mesh with alternating planting of perennial ryegrass and bermudagrass ensure overall slope stability and facilitate deformation control.
出处
《重庆建筑》
2025年第9期81-87,共7页
Chongqing Architecture
关键词
膨胀土
数值模拟
降雨
生态防护
边坡
Expansive Soil
Numerical Simulation
Rainfall
Ecological Protection
Slope
