塑性混凝土防渗墙在黄河堤防土石结合部防渗加固中的应用研究

发布时间：2018-03-29 00:23

本文选题：塑性混凝土　切入点：真三轴试验　出处：《华北水利水电大学》2017年硕士论文

【摘要】：塑性混凝土在实际防渗墙工程应用中一般处于三维受力状态,且周围应力又随水位的涨落等环境因素发生改变,但围压变化对塑性混凝土力学性能的影响规律还不清楚。本文针对这一问题通过48组塑性混凝土真三轴压缩应力-应变全曲线试验和18组卸围压应力-应变全曲线试验,结合不同膨润土掺量研究其力学性能和破坏形式;通过数值分析软件来模拟塑性混凝土作为防渗材料在除险加固工程上的抗渗效果和整体稳定性能,主要内容如下:(1)对围压恒定真三轴试验数据用科学应变计算方法进行修正,修正后峰值强度降低,幅度在5%~10%;当最小主应力相同时,塑性混凝土的峰值强度随中间主应力的增大而增大,但增幅越来越小;峰值后曲线特征由近似塑化状态变为具有明显峰值点和明显下降段;给出塑性混凝土真三轴受压破坏公式:τ_0=-0.027+1.335σ_0-0.133σ_0~2(2)通过塑性混凝土卸侧压三轴压缩试验,研究了侧压条件一致的情况下,卸载同一侧围压时,不同膨润土掺量对塑性混凝土破坏类型的影响;在相同配合比情况下,卸载同一侧围压时,不同围压条件对塑性混凝土破坏类型的影响;破坏形式主要有类似单轴试验的脆性破坏和类似单轴试验的延性破坏。(3)经过数值分析表明,布设塑性混凝土防渗墙后浸润线明显降低,孔隙水压力、水头和水力坡降迅速减小,地基土层内和土石结合部的渗流流速也明显减小;水位降低时涵洞入口周围的坡面和坡底处会出现较大变形,最大变形量为2mm左右,应力云图上对应相同位置出现了拉应力和应力集中现象;防渗墙墙体内以受压应力为主,并未出现应力集中和不均匀沉降现象。
[Abstract]:The plastic concrete is generally in a three-dimensional stress state in the application of practical impervious wall engineering, and the surrounding stress changes with the fluctuation of water level and other environmental factors. However, the influence of confining pressure on the mechanical properties of plastic concrete is not clear. In this paper, 48 groups of true triaxial compression stress-strain full curve tests and 18 sets of unloading confining stress-strain complete curve tests are adopted to solve this problem. Combined with different bentonite content, the mechanical properties and failure forms of plastic concrete are studied, and the seepage resistance and overall stability of plastic concrete as anti-seepage material are simulated by numerical analysis software. The main contents are as follows: (1) the data of the true triaxial test of constant confining pressure are corrected by scientific strain calculation method. After the correction, the peak intensity decreases and the amplitude is 5 ~ 100.When the minimum principal stress is the same, The peak strength of plastic concrete increases with the increase of intermediate principal stress, but the increase is smaller and smaller. In this paper, the failure formula of plastic concrete under true triaxial compression is given: 蟿 0 + -0.027 蟽 -0.027 蟽 0-0.133 蟽 0 / 2). Through the triaxial compression test of plastic concrete under unloading lateral compression, it is studied that under the condition of the same lateral compression condition, when the same lateral pressure is unloaded, The influence of different content of bentonite on the failure type of plastic concrete and the influence of different confining pressure on the failure type of plastic concrete under the same mixing ratio and unloading the same lateral confining pressure; The main failure forms are brittle failure similar to uniaxial test and ductile failure similar to uniaxial test. The numerical analysis shows that the infiltration line of plastic concrete cutoff wall is obviously reduced, pore water pressure, head and hydraulic gradient are decreased rapidly. The velocity of seepage flow in the soil layer and the junction of soil and rock also decreases obviously, and when the water level decreases, the slope surface and the slope bottom around the entrance of culvert will be deformed, the maximum deformation is about 2mm. Tensile stress and stress concentration appear at the same position in the stress cloud map, and compressive stress is the main stress in the wall wall, but there is no stress concentration and uneven settlement in the wall.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV871;TV543.82

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