考虑混凝土衬砌板与冻土接触非线性的渠道冻胀数值模拟  

Numerical simulation of canal frost heaving considering nonlinear contact between concrete lining board and soil

作　　者：李爽[1] 王正中[1,2] 高兰兰[1] 刘铨鸿[1] 王文杰[1] 孙杲辰[1] 

机构地区：[1]西北农林科技大学水利与建筑工程学院,陕西杨凌712100 [2]中国科学院寒区旱区环境与工程研究所冻土国家重点实验室,甘肃兰州730000

出　　处：《水利学报》2014年第4期497-503,共7页Journal of Hydraulic Engineering

基　　金：国家自然科学基金资助(51279168);国家科技支撑计划资助(2012BAD10B02);冻土工程国家重点实验室项目资助(SKLFSE-201105);陕西水利科技专项(SXSL2011-03);博士点基金(20120204110024)

摘　　要：旱寒灌区渠基土中水分在温度梯度作用下向冻结锋面迁移聚集并冻结膨胀,使其上混凝土衬砌板冻胀破坏,以往的线弹性分析方法在数值模拟中将冻土与混凝土衬砌板视为一体,无法反映两者之间的滑移。本文采用符合冻土与混凝土接触面冻结特性的非线性本构模型来合理反映两者的相对滑动及脱离,考虑混凝土的弹塑性及其与冻土的接触非线性,建立能反映混凝土板从弹性到塑性屈服失效过程的渠道冻胀破坏数值模型,并对冻胀过程进行分析。结果表明,未考虑接触非线性的切向冻结力会超过混凝土与冻土最大冻结强度,不符实际;而考虑接触非线性的数值模型更能反映衬砌渠道冻胀破坏过程,更能合理解释渠道冻胀破坏位置在渠底中间和阴阳坡靠近渠底1/3板长处,切向冻结力、法向冻胀力最大值较未考虑接触非线性的要小约50%且分布更均匀。In the base frozen soil of canal, unfrozen water migrates under the effect of temperature gradi-ent and gathers at freezing front, resulting in the frost heaving of base soil. Constraint by the lining con-crete plate on it, frost heaving effect is reduced which in return will lead to the initiation of tensile stress in lining concrete plate. When the tensile stress in lining concrete exceeds its yield strength, fracture emerges and forms a leakage passage of water, causing a waste of water. A finite element model is there-fore established with the goal to resolve this problem and to study the failure mechanism of canal frost heaving. Taking lining concrete plate and canal base frozen soil as two different parts, a constitutive model which can reflect the nonlinear contact characteristics between concrete and frozen soil is applied. Com- pared with those without considering contact, this model can reflect the reasonable relative displacement be- tween frozen soil and lining board, i.e. slide and open. Meanwhile, concrete is considered as an elastic plastic material. Results from simulations show that tangential adfreezing force of model without considering contact is 50% greater than that of the other, with its largest amount exceeding its actual limit（the frozen strength between frozen soil and concrete）, while the other not, Also evident is that the distribution of both plastical strain and tangential adfreezing force in the latter model can illustrate that the middle of ca- nal bottom and 1/3 plate length of lining concrete plate near the bottom is the most vulnerable parts.

关 键 词：渠道冻胀 非接触单元 数值模拟 混凝土损伤塑性 

分 类 号：S277[农业科学—农业水土工程] TV698.26[农业科学—农业工程]