地下连续墙岩溶侧壁稳定性分析方法

Stability Analysis Method for Karst Sidewalls of Ground-Linked Wall

针对目前岩溶侧壁稳定性分析不完善问题,考虑地连墙浇筑溶洞侧壁压力分布规律及溶洞空间形态特征。首先,将岩溶侧壁简化为固支梁、抛物线及圆弧拱模型,推导出三种模型在梯形分布荷载作用下的最大弯矩计算公式,建立各模型的岩溶侧壁抗弯最小安全厚度计算方法;通过典型案例进行岩溶侧壁受压破坏影响因素分析,揭示了岩溶侧壁最小安全厚度随溶洞的矢高、跨度、岩石抗拉强度及埋深的变化规律;然后,构建了岩溶侧壁稳定性分析方法;最后,通过案例分析,确定了岩溶侧壁稳定性评价结果的合理性。结果表明:溶洞矢跨比为0~0.01时,可采用相对简单的梁模型进行计算;矢跨比为0.01~0.2时,抛物拱与圆弧拱模型计算所得最小安全厚度值差别较小。

In response to the current problem of incomplete stability analysis of karst sidewalls,the distribution law of pressure on the sidewalls of karst caves during the pouring of underground connecting walls and the spatial morphology characteristics of karst caves are considered.Firstly,the karst sidewall is simplified as a fixed beam,parabolic,and arc arch model,and the maximum bending moment calculation formulas for the three models under trapezoidal distributed loads are derived.The calculation method for the minimum safe bending thickness of the karst sidewall for each model is established;Secondly,through typical cases,the influencing factors of karst sidewall compression failure were analyzed,revealing the variation pattern of the minimum safe thickness of karst sidewall with the height,span,rock tensile strength,and burial depth of the karst cave;Then,a method for analyzing the stability of karst sidewalls was constructed;Finally,through case analysis,the rationality of the stability evaluation results of karst sidewalls was determined.The results indicate that a relatively simple beam model can be used for calculation when the rise span ratio of the karst cave is 0-0.01;When the rise span ratio is 0.01~0.2,the difference in the minimum safe thickness calculated by the parabolic arch and circular arch models is small.