考虑冻胀力和冻结力作用的梯形渠道衬砌冻胀破坏弹性地基梁模型

Elastic foundation beam model for frost heave damage of trapezoidal canal lining considering frost heave force and adfreeze force

考虑基土冻胀作用于衬砌的法向冻胀力与界面冻结力的关系,基于弹性地基梁理论,建立开放系统中梯形渠道衬砌的冻胀破坏力学模型,使用解析法得到衬砌冻胀变形和内力解。通过与原型渠道及已有研究的冻胀变形进行对比,验证计算的正确性。研究结果表明:坡板最大冻胀变形发生在距离坡脚43%坡板长度处,最大弯矩发生在距离坡脚25%坡板长度处,这与已有的研究成果中梯形渠道衬砌破坏主要发生在距离渠坡坡脚25%~45%坡板长度处吻合。当考虑界面冻结力时,冻结力对挠度和剪力影响较小,而对弯矩的影响较大。界面的冻结力相当于作用于梁上的偏心拉压荷载,对弯矩有正叠加作用。因此,当仅考虑衬砌的刚度时,可不考虑冻结力的影响;但当重点考虑衬砌的强度时,应考虑界面冻结力的影响。

The relationship between the normal frost-heave force and the interface adfreeze force was considered,the frost heave failure mechanical model of the trapezoidal channel lining in the open system was established based on the elastic foundation beam theory, and the analytical solution was obtained to calculate deformation and internal force of lining. The correctness of the calculation was verified against an existing experimental and analytical results. The results show that the maximum frost-heave displacement of the slope lining occurs at distance from the position of 43% of the slope lining based on an engineering case, and the maximum bending moment occurs at distance from the position of 25% of the slope lining. This is corresponding to the existing result that the lining failure takes place at a distance of 25% to 45% lining length from the toe. Moreover, the interface adfreeze force has a little effect on deflection and shear force of the lining, but it has a greater effect on the bending moment of lining. The adfreeze force is an eccentric load acting on the beam, and has a positive superimposition effect on the bending moment. Therefore, in the design process, when only the stiffness of the lining is considered, the effect of adfreeze force may not be considered;but when focusing on the strength of the lining, the influence of the interface adfreeze force should be considered.