基于扩展有限元法的水工压力隧洞水力劈裂分析

Hydraulic fracturing analysis of hydraulic pressure tunnel based on extended finite element method

考虑裂隙面水压力作用的虚功原理,采用扩展有限元法分析水工压力隧洞水力劈裂问题的控制方程,对水工压力隧洞的水力劈裂进行了数值模拟分析。计算结果表明,水力劈裂对隧洞内壁周边应力场的影响较大,对远离隧洞内壁处应力场的影响较小,考虑水力劈裂计算得到的环向位移要大于不考虑水力劈裂计算得到的环向位移;水力劈裂对II型应力强度因子影响较小,水力劈裂导致I型应力强度因子增大;侧压力系数对II型应力强度因子影响较小,对I型应力强度因子影响较大,且随着侧压力系数增大,I型应力强度因子也不断增大;随着裂隙扩展,洞顶和洞右侧控制点的径向位移不断增大,而洞右侧与洞左侧的环向位移也不断增大。

Considering the virtual work principle of the hydraulic pressure on the fracture surface,the extended fi⁃nite element method was used to analyze the governing equation of the hydraulic splitting problem of the hydraulic pressure tunnel,and the hydraulic splitting of the hydraulic pressure tunnel was numerically simulated and ana⁃lyzed.The calculation results showed that the hydraulic fracturing had a great influence on the stress field around the inner wall of the tunnel,and a small influence on the stress field far away from the inner wall of the tunnel.The circumferential displacement calculated with hydraulic fracturing was greater than that calculated without hydraulic fracturing.Hydraulic fracturing had little effect on type II stress intensity factor,while hydraulic fracturing caused type I stress intensity factor to increase.The side pressure coefficient had little influence on the type II stress inten⁃sity factor,but had a great influence on the type I stress intensity factor.With the increase of the side pressure coef⁃ficient,the type I stress intensity factor also increased.With the crack expansion,the radial displacement of the control points on the top and right side of the tunnel increased continuously,and the circumferential displacement of the right and left sides of the tunnel also increased continuously.