深厚砂性土地基大型水闸闸基防渗设计研究

Anti-seepage design of large sluice foundation in deep sandy soil foundation

为研究某深厚砂性土地基大型水闸防渗设计方案,分别应用AutoBank软件和MIDAS有限元软件进行了渗流和应力变形计算分析。研究表明:不设防渗墙或设置悬挂式防渗墙时,闸基出口段最大坡降均小于出口段允许坡降值,而水平段最大坡降均大于水平段允许坡降值且渗漏量较大,设置防渗墙入基岩1m,满足渗流要求;防渗墙上部以拉应力为主,下部以压应力为主,最大压应力出现于地层分界位置,但均未超过混凝土设计抗拉抗压强度;在临近地层分界线的上部区域以及底部嵌固端,普通混凝土防渗墙与塑性混凝土防渗墙有较大的区别,普通混凝土防渗墙在地层分界线上部区域最大拉应力值为0.37MPa,底部嵌固端最大拉应力值为1.46MPa,后者超过了混凝土设计抗拉强度,塑性混凝土防渗墙在上述部位无拉应力;普通混凝土防渗墙及塑性混凝土防渗墙水平位移基本一致,塑性混凝土防渗墙竖向位移较普通混凝土防渗墙大。

In order to study the anti-seepage design scheme of a large sluice in deep sandy soil foundation,AutoBank software and MIDAS finite element software were used to calculate and analyze the seepage and stress deformation.The research shows that when there is no cutoff wall or suspended cutoff wall,the maximum slope of the outlet section of the sluice foundation is less than the allowable slope of the outlet section,while the maximum slope of the horizontal section is greater than the allowable slope of the horizontal section and the leakage is large.The upper part of the cutoff wall is mainly tensile stress,but it does not exceed the design tensile strength of concrete.The middle and lower part of the cutoff wall is dominated by compressive stress,and the maximum compressive stress appears at the stratum boundary,but it does not exceed the design compressive strength of concrete.The stress distribution of ordinary concrete cutoff wall and plastic concrete cutoff wall is quite different in the upper area near the stratum boundary and the bottom embedded end.The maximum tensile stress of the ordinary concrete cutoff wall in the upper part of the stratum boundary is 0.37 MPa,and the maximum tensile stress value of the bottom embedded end is 1.46 MPa,which exceeds the design tensile strength of the concrete.The plastic concrete cutoff wall has no tensile stress at the above parts.The horizontal displacements of ordinary concrete cutoff wall and plastic concrete cutoff wall are basically the same,but because of the low elastic modulus of plastic concrete cutoff wall,the vertical displacement of plastic concrete cutoff wall is larger than that of ordinary concrete cutoff wall.