基于局部测量方法的堆石料变形特性试验研究

Experimental Study on Deformation Characteristics of Rockfill with Local Measurement Method

在大型三轴仪中联合采用了局部轴向位移计和径向变形测量位移传感器,通过直接测量试样局部的轴向应变和径向应变,排除了端部误差的影响。在此基础上研究了堆石料小应变阶段的变形规律。试验结果表明:轴向应变在0.001%~0.01%的范围时,局部位移计测定的割线模量是外部位移传感器测量结果的1.5~2.0倍,当轴向应变达到1%时两者测定的割线模量基本一致;传统测量方法会明显高估试样的实际体应变,低估径向应变,在小应变阶段局部测量方法测定的泊松比约为传统测量方法的2.0倍。

It is very important to evaluate the deformation law of the dam by accurately measuring the deformation characteristics in the small strain stage. Because of the existence of end errors,the traditional large triaxial apparatus can not accurately measure the deformation characteristics of rockfill in the small strain stage. So local axial displacement transducer and radial displacement transducer are used in the large triaxial apparatus,measuring the local axial strain and radial strain directly,and the effects of the end errors are eliminated. By using this technique we study the deformation characteristics of rockfill in the small strain stage. The results show that the secant modulus measured by local axial displacement transducer is 1. 5 to 2. 0 times of the results measured by external displacement transducer when axial strain is between 0. 001% and 0. 01%. When the axial strain comes to 1%,the results achieved by two different means become consistent basically. Traditional measuring method overestimate the volumetric strain and underestimate the radial strain. The poisson＇s ratio measured by local deformation is about 2.0 times of the result measured by traditional means in the small strain range.