含水率对泥石流浆体力学特性影响实验研究

Experimental Study on Influence of Water Content on Mechanical Properties of Debris Flow Slurry

探讨含水率对泥石流浆体力学特性影响是泥石流运移过程研究的基础性内容。以成都龙泉区黏土为实验材料,配制11种不同含水率的泥浆,利用安东帕MCR301流变仪,对不同含水率泥浆开展两循环旋转剪切实验(每循环剪切过程分为增速剪切(0-30 s^(-1))和减速剪切(30-0 s^(-1))两阶段),分析含水率对泥浆剪切过程、剪应力变化过程、剪切应力峰值及灵敏度的影响。实验结果表明:①初剪应力峰值和复剪应力峰值与含水率呈幂律关系。②由于剪切过程的差异性导致含水率对泥浆的剪应力与剪切速率的影响也具有差异性:当含水率低于100%时,第一、第二循环各阶段剪切过程中剪切应力变化过程完全不重合,且初剪应力峰值和复剪应力峰值随含水率增大迅速降低,灵敏度随含水率的增加迅速减小到1;当含水率高于100%时,第一、第二循环各阶段剪应力变化过程基本一致,含水率对应力峰值和泥浆灵敏度的影响可以忽略不计。③影响成都黏土泥浆剪切过程、剪切应力变化、剪应力峰值和灵敏度的含水率阈值是100%。本文对成都区黏土泥浆开展了动态剪切试验,探讨了含水率对泥浆特性的影响,可为其他区域黏土特性的研究提供参考,具有重要的研究意义!

The influence of water content on the mechanical properties of mud is the basic content of the study on the moving process of debris flow disaster.Using the clay in Longquan District of Chengdu as the experimental material,11 kinds of mud with different water content (50%,57%,63%,67%,72%,80%,101%,131%,182%,302%,and 400%) were prepared.To analyze the effect of water content on mud shearing process,shear stress change process,shear stress peak and sensitivity,two cycles of rotary shearing experiments were carried out on mud with different moisture content by using Anton Paar MCR301 rheometer.Each cyclic shear process was divided into two stages: accelerated shear (0~30 s^-1 ) and decelerated shear (30~0 s^-1 ).The experimental results showed that: The peak shear stress of the first and of the second cycles had a strong power relationship with the moisture content.The influence of moisture content on the shear stress of slurry was different: The shear stress change processes were completely different in each stage of the first and the second rotary shearing process,and the shear stress peak value of the first and the second cycles decreased rapidly,and the sensitivity decreased rapidly to 1 with the increase of the moisture content,when the moisture content was lower than 100%.However,the change processes of shear stress in each stage of the first and second rotary shearing were basically the same,and the shear stress peak value of the first and the second cycles decreased slowly with the increase of moisture content,and the influence of moisture content on sensitivity of slurry could be ignored,when the moisture content was higher than 100%.This study also indicated that the moisture content threshold affecting Chengdu clay mud shear process,shear stress change,shear stress peak and sensitivity was 100%.In this paper,a dynamic shear tests were carried out on the clay slurry in Longquan District of Chengdu,and the influences of water content on the mud characteristics were fully discussed.It provided reference for the study of clay properties in other areas,and had important research significance.