引江济淮工程江淮分水岭软弱夹层对边坡稳定的影响

引江济淮工程江淮分水岭局部存在顺坡向缓倾角夹层,施工期部分深挖方河渠因开挖时间长,已经出现了局部滑坡,初步分析结果表明这与夹层岩土体在大变形条件下强度已接近残余状态有关。为了分析夹层对边坡稳定的影响,对滑坡渠段的原状地层进行了取样,分析了渠坡软弱夹层的强度特性,并结合实际工程断面开展边坡稳定分析,提出了处理措施建议。研究表明,本工程渠坡稳定性取决于渠坡软弱夹层的位置、倾向和力学指标,滑坡部位软弱夹层在大变形的持续作用下已处于残余强度状态,并引发了局部滑坡。为此,对本工程深挖方渠段应结合渠坡岩土的分层结构及强度特性,采用抗滑桩和锚固等支档措施进行加固,同时应做好渠坡排水。

Influence of Weak Interlayer on Slope Stability in Jianghuai Watershed of Yangtze-to-Huaihe River Water Diversion

Due to the bedding weak interlayer with gentle dip angle along the slope of Yangtze-to-Huaihe River Water Diversion in Jianghuai watershed, parts of canal slope have been excavated for a long time during construction, resulting in increased deformation of interlayer and slope collapse. Preliminary analysis reveal that the strength of the interlayer rock mass is close to residual state under the condition of large deformation. To investigate the influence of interlayer on slope stability, we collected undisturbed soil samples from some deep excavated canal sections and examined the strength characteristics of weak interlayer and carried out slope stability analysis, and also put forward some suggestions of treatment measures. Stability analysis unveil that the canal slope stability depends on the position, tendency and mechanical indexes of the weak interlayer in canal slope. The weak interlayer of canal slope has been in the state of residual strength under the continuous action of large deformation, which leads to local collapse. We suggest to reinforce the slope with retaining measures such as anti-slide pile and anchorage in association with slope drainage in line with the layered structure and strength characteristics of the canal slope.