水位降低引起的冰盖对水工建筑物拉拔力作用研究

Pulling effect of ice sheet caused by water level decreasing on hydraulic structures

为了研究寒冷地区冬季水库水位下降过程中,冰盖对水工建筑物的拉拔力作用,文中以冰盖为研究对象,采用扩展有限元方法(XFEM)运用ABAQUS软件获取存在初始裂纹的冰盖在水位下降过程中对约束端产生的作用以及不同约束端对拉拔力的影响。结果表明:水位在下降速率为0.8 m/h的过程中,初始裂纹在48 min时贯穿冰盖,使其发生完全断裂,此时约束端受到的剪力和弯矩最大,分别为0.218 MPa和181 k N·m;48 min以后,约束端只受到剩余冰盖在自重作用下对其产生的作用力;水位下降速率越大,冰盖裂纹在同等水位下降时间内扩展范围越广。斜墙约束下的冰盖较直立墙约束下的冰盖对约束端会产生较大的剪力和较小的弯矩。

In order to study the effect of ice sheet on the drawing force of hydraulic structures during the decline of water level in winter cold area,the ABAQUS finite element software and extended fi-nite element method （ XFEM ） were used to study the effects of the ice sheet with initial crack on the restraint and the influence of the different restraints on the drawing force caused by water level de-crease. The results show that when the water level decreased at the rate of 0. 8 m/h, the initial crack passed through the ice sheet and caused it to break completely. At this moment,the restraint was subjected to the maximum shear force 0.218 MPa and bending moment 181 kN ？ m. Then the restrained side was only under the action of its own gravity with the remaining ice sheet. The faster the water level descending, the larger the lengths of the ice sheet crack in the same time. By compa-ring the different geometric constraint boundary conditions,it can be found that the ice sheet under the constraint of the oblique wall has larger shear force and smaller bending moment than on the straight wall restraint.