考虑井帮收敛的深冻结壁弹塑性设计方法

An elastoplastic design method for deep frozen wall considering shaft-flank displacement convergence

为研究井帮位移收敛对冻结壁厚度的影响,获得满足施工要求的开挖净空间,基于小孔扩张理论,建立井帮变形与冻结壁厚度的计算公式,验证已建公式的正确性,探讨已建公式对井帮变形的计算误差。结果表明:随着冲积层深度增大,井帮位移收敛对冻结壁厚度的影响加剧,冲积层深度越大,越不能忽略井帮收敛的影响;已建公式能够解决应变高达0.15的有限变形问题,亦可有效预测千米冲积层立井井帮位移收敛值;冻土的黏聚力和内摩擦角对冻结壁厚度影响显著,弹性模量和黏聚力是井帮变形的重要影响因素。研究成果对深厚冲积层冻结法凿井具有重要的理论意义和实用价值。

In order to investigate the influence of shaft-flank displacement convergence on frozen wall thickness and obtain excavated desired clearance meeting construction requirements,a calculation formula of side-wall deformation and frozen-wall thickness was established based on the cavity expansion theory.The established formulas was verified and the calculation errors of the established formulas on shaft-flank deformation were discussed.The results indicated that the effects of sidewall displacement convergence on a frozen wall thickness increased with the increase of alluvium depth.The greater the alluvium depth was,the more the influence of sidewall convergence could not be ignored.The established formulas solved a finite deformation problem with strain of up to 0.15 and effectively predicted the shaft-flank displacement convergence of a kilometer alluvium shaft.The cohesion and internal friction angle of frozen soil had a significant impact on frozen wall thickness.The elastic modulus and cohesion were important factors affecting shaft-flank deformation.The research results had an important theoretical significance and application value for the deep alluvium freezing shaft sinking.