高寒地区灌溉渠系的防冻胀设计

Design Preventing Frozen Bulge Damage of Irrigation Canals in Bad Cold Area

西藏那曲地区气候高寒,渠道冻胀破坏严重。通过才曲塘人工草场灌溉渠系的修建,分析了引起该区渠道冻胀的气候、地质等主要因素,提出了新建渠道时规划和设计方面的防冻胀措施。规划中要依据地质条件选择透水性较强的砂砾石地段,依据地下水条件选择地下水位埋藏较深的地段,依据地形地貌条件选择地形较高的脊梁地带或尽量采用填方渠道规划渠系。设计中对于挖方渠道,采用适变断面、换填、设置排水、保温和架空衬砌等措施,以适应和回避冻胀;对于填方渠道,采用架空渠槽或道渣石垫层明设的措施,以消减或消除冻胀。这些措施对高寒高海拔地区渠道建设具有一定的指导意义。

For the bad cold weather, the canals are damaged very seriously by frozen bulge in the district of Naqu Tibet. Based on the irrigation canals construction of the artificial grassland at Caiqutang, this paper analyzed the main factors that caused the canals damaged, such as climate and topography condition etc. The paper put forward measures to prevent frozen bulge during the design and constructing stages. In designing, select easily permeate sand gravelly stone area depending on topography, select deeper district on groundwater level, select the top back district and apply filling canals depending on earth and topography conditions respectively. In constructing, for the cutting canals, to apply typical balanced section and change fill materials and suspend lining bulkhead are the better ways to balance and avoid frozen bulge. For the filling canals, to apply gravelly stone lining opened and suspend canal location are the better ways to reduce and diminish frozen bulge. Meanwhile, these ways will play a certain guidance role in the high altitude and bad cold weather area.