双排钢板桩围堰结构选型设计与计算

双排对拉钢板(管)桩围堰是堰筑隧道常用的围堰形式,围堰结构选型设计(刚度选型、是否采取地基处理或反压土护脚等)往往差异较大。文章通过对围堰结构选型进行综合对比论证,同时采用通用有限元软件SAP2000对各种处理手段的影响进行计算分析,计算填土工况和抽水工况两种工况条件下的钢板桩弯矩、内力、位移以及拉杆轴力等,对数据进行分析。结果表明,提高自身刚度可以减小变形及应力,但并不是线性关系,地基处理和反压土效果基本相当,可有效降低拉杆轴力、板桩弯矩、应力及变形等各参数。因此,围堰结构选型首先应根据地质条件、水文条件选定合适刚度的钢板(管)桩型号,再根据实际工程情况,选择地基处理或反压土等处理方式。

Structure Design and Calculation of Double-row Steel Sheet Pile Cofferdam

Double-row steel sheet pile cofferdam is a common form of cofferdam for weir tunnel construction in recent years.The selection and design of cofferdam structure(rigidity selection, foundation treatment or back pressure soil toe protection, etc.) are often quite different. In this paper, through comprehensive comparison and demonstration of cofferdam structure selection, the general finite element software SAP2000 is adopted to calculate and analyze the influence of various treatment methods, calculate the bending moment, internal force, displacement and axial force of steel sheet pile under the two working conditions of filling soil and pumping water, and analyze the data. The results show that the improvement of stiffness can reduce the deformation and stress, but the relationship is not linear. The effect of foundation treatment and reverse compaction is basically the same, which can effectively reduce the axial force of tie rod, the bending moment of sheet pile, stress and deformation, and other parameters. Therefore, the selection of cofferdam structure should first choose steel plate(tube) pile type with appropriate stiffness according to geological and hydrological conditions, and then choose foundation treatment or reverse compaction treatment according to actual engineering conditions.