某泄水闸渗流及扬压力分析

Analysis of seepage and uplift pressure of a sluice

水利工程基岩的渗透性会因为构造裂隙的存在而发生改变,产生的扬压力会增强坝基的滑动力,增大坝基出现破坏的概率,所以研究其渗流特性的变化十分重要。以某大坝泄水闸为例,根据其基岩的结构特点,通过建立数值模型分析水闸裂隙岩体的渗流情况,研究结果表明:未设置防渗帷幕时,监测所得流量最大值、最低值和平均值均高于设置防渗帷幕,后者比前者结构面内的流量平均值减小了0.54×10^(3)m^(3)/s,减小了23.3%,表示防渗帷幕有较好的防水效果;有帷幕时的扬压力要低于无帷幕工况,有帷幕时和无帷幕时的平均扬压力值分别为0.43MPa和0.56MPa,前者与后者相比降低了近30%;加上动力荷载能够明显增大渗流量,渗流量在无动力工况和有动力工况的平均值分别为2.13×10^(-3)m^(3)/s和2.66×10^(-3)m^(3)/s,提高了近19.9%;扬压力在有帷幕工况和无帷幕工况下的平均值分别为0.743MPa和0.589MPa,增加近20.7%。

The permeability of bedrock in hydraulic engineering will change due to the existence of structural cracks,and the resulting uplift pressure will enhance the sliding force of dam foundation and increase the probability of dam foundation failure,so it is very important to study the change of seepage characteristics.Taking the sluice of a dam as an example,according to the structural characteristics of its bedrock,a numerical model is established to analyze the seepage of fractured rock mass in sluice.The research results show that:When the anti-seepage curtain is not set,the maximum,minimum and average of the monitored flow are higher than that of the anti-seepage curtain.The latter decreases by 0.54 × 10^(3)m^(3)/s and 23.3%compared with the former,indicating that the anti-seepage curtain has a better waterproof effect.The lifting pressure with curtain is lower than that without curtain.The average lifting pressure with curtain and without curtain is 0.43 MPa and 0.56 MPa respectively,and the former is nearly 30%lower than the latter.In addition,dynamic load can significantly increase the seepage flow,and the average seepage flow in the non-dynamic condition and the dynamic condition are 2.13×10^(-3)m^(3)/s and 2.66×10^(-3)m^(3)/s,respectively,increasing by nearly 19.9%.The average lfting pressure under curtain condition and no curtain condition is 0.743 MPa and 0.589 MPa respectively,increasing by nearly 20.7%.