基于温度-应力耦合的冻土地区渠道衬砌防冻胀效果及适应性评价

中国北方冻土地区的灌区渠道多采用衬砌或者保温措施进行防渗抗冻胀,从而减少输水损失。依据近年来北方冻土地区常用的渠道衬砌形式,从取材和施工的难易程度等角度,对北方高寒地区新疆阿勒泰灌区农十师渠道3种抗冻胀措施的效果进行了研究,分别建立了混凝土、HAS固化剂固化粉煤灰和聚苯乙烯泡沫板(EPS)3种衬砌材料的本构模型。通过ABAQUS温度-应力耦合模拟,分析了3种抗冻胀措施的效果。分析结果表明:3种抗冻胀措施均能有效减少渠道冻胀变形,而HAS固化剂固化粉煤灰和铺设聚苯乙烯泡沫板削减冻胀变形效果更为显著;其中铺设聚苯板措施效果最佳,不仅使混凝土衬砌最大法向冻胀量削减了54%,法向冻胀力削减了74%,切向冻结力削减83%,而且使应力和位移分布更均匀,避免了应力集中现象的发生。3种防冻胀措施的效果为铺设聚苯板>HAS固化粉煤灰>混凝土衬砌。考虑到HAS固化粉煤灰可实现就地取材,从而得出HAS固化剂固化粉煤灰渠道衬砌适用于新疆等寒冷地区的结论。研究成果为寒冷地区渠道抗冻胀设计提供了有效参考。

Evaluating the Effectiveness and Adaptability of Anti-frost-heaving Materials for Channel Lining in Frozen Earth Areas Based on Temperature-Stress Coupling

In frozen earth areas of North China, lining and insulation measures are usually adopted to prevent seepage and frost heave in many irrigation channels, thereby reducing water loss. In this research, the effects of three different anti-freezing measures of channel lining for the irrigation channels in Nongshi Division of Altay, Xinjiang, were comparatively studied in terms of material acquisition and construction. The constitutive models of three lining materials, namely, concrete, fly ash solidified by HAS curing agent, and polystyrene foam board (EPS board), were established. The anti-frost-heaving effects of the three lining materials were analyzed via temperature-stress coupled simulation in ABAQUS. Results reveal that the three measures are capable of reducing the frost heave deformation of channels. Compared with concrete lining, fly ash solidified by HAS and EPS foam board linings provide with better effects, of which the EPS foam board performs the best by cutting the maximum normal frost heave displacement by 54%, normal frost heave force by 74%, and tangential frost force by 83%. EPS foam board also facilitates the uniform distribution of stress and displacement, and consequently, refrains from stress concentration. The anti-frost-heaving effect of polystyrene board is the most superior, followed by that of fly ash solidified by HAS, and concrete lining in sequence. Nevertheless, fly ash solidified by HAS could be a potential material of channel lining in highly cold areas like Xinjiang as fly ash can be acquired locally.