Numerical Study on Structural Modification of Channel Lining in Cold and Arid Zones with Wet Submerged Land Base
The anti-seepage lining structure of water conveyance channels in cold and arid regions is prone to frost heave damage,which affects the safety of water supply and stable operation of water supply in irrigation areas.In order to improve the frost heave resistance of collapsible loess foundation channels,taking the lining channels in Ningxia Guhai Yangshui irrigation area as an example,through analysis of the freezing and expansion damage characteristics of the pro-totype channels,based on the idea of improving the frost heave deformation resistance of impervious body,three kinds of anti-seepage structure optimization schemes with different slope coefficients,cross-section structural forms and slope con-struction materials were proposed.The frost heave deformation characteristics and stress state of lining structures of dif-ferent schemes under thermal coupling were analyzed respectively.The results show that the arch bottom trapezoidal channel has better frost heave resistance than trapezoidal channel in collapsible loess area;Adding a certain thickness of cement mortar bedding layer between the base soil of channel seepage control lining body can effectively attenuate the stress concentration phenomenon of the lining structure under the action of freezing and expansion;Appropriately reduc-ing the coefficient of side slope of the channel can effectively reduce the peak of the freezing and expansion stresses in the channel.In the three kinds of lining reconstruction structures,the peak stress reduction amplitude is 70.49％,63.36％and 27.68％,the maximum frost heave reduction rate is 7.70％,5.05％ and-2.82％,and the slope coefficient is 1:1.75 arc bottom trapezoid section type.It has the best anti-frost heave effect and can be popularized and applied in similar areas.The results of this study provide reference for the structural modification of irrigation channels across wet sub-sidence loess foundations,and can also provide a basis for the anti-freezing and expansion design of channels in similar areas.
lined channelsfrost damagemortar beddingfinite element methodthermal couplingnumerical sim-ulation
NETL
NSTL
万方数据
维普
