膨胀土边坡失稳机理与加固技术研究

Study of the Instability of Expansive Soil Slopes and Their Improvement Techniques

在膨胀土边坡病害处治工程中,对边坡范围内的土层分布、工程与水文地质条件等进行分析后,发现裂缝开展是导致边坡滑移的主因;结合桥墩桩体裂缝、桥头附近沥青路面层横向张拉裂缝的位置,确定出可能的软弱滑动面(带),并利用Geo-Slope软件评价其稳定性;基于极限平衡理论,运用反演分析方法,给出合乎实际的滑带土综合抗剪强度指标值;提出了总体整治方案。

This case history presents the treatment of expansive soil slope instability hazards near a bridge construction site. From the soil stratigraphy within the affected slopes, physical and mechanical properties of various soil strata as well as the bydrogeological conditions, it is identified that the initiation and the development of the fissures are the main factors that cause adverse movement of the slope in expansive soils. The limits of the weak zone can be estimated from the locations of the cracks near the bridge piers and the transverse tension cracks near the abutment pavement. The stability of the affected zones is evalu- ated by the software GEO-SLOPE. Based on the failed slopes at the bridge site, the shear strength parameters are back-ana- lyzed using the limit equilibrium theory. The rehabilitation program includes anti-slope piers with a rectangular cross-section, local unloading, as well surface drainage improvements.