摘要
由于土压力盒材料与砂土在物理力学性质上的差异,在刚性加载砂标试验中土压力盒受力面易出现拱效应、应力重分布和应力分散等问题,导致刚性加载在很多砂标试验中的适用性较差。针对上述问题,基于缩小加载面积和介质空间的思路设计出新型的砂标试验方法——应力集中砂标法。采用刚性加载试验法和应力集中砂标试验法对3种不同规格的土压力盒进行室内标定试验,将2种试验法获得的标定结果与厂家气标结果进行对比。结果表明:新型试验方法获得的标定曲线离散率均较低,标定结果满足室内试验的精度要求,具备现场应用价值;刚性加载试验标定结果相较气标值偏小,而应力集中砂标法的标定结果相较气标值偏大,表明在质地松软、颗粒孔隙率较大的砂标试验环境中,应力集中砂标法具有更强的适用性。
Several negative factors like soil arching effects,redistribution of stress,dispersion of stress and so on are easily arise on the force surface during the rigid loading calibrations of earth pressure cells in sand soil due to the larger difference in the physical and mechanical properties between earth pressure cells’material and sand soil,which result in the poor application of rigid loading method in the calibration tests.To solve above problems,the author designed a new pressure cells calibration method—Stress concentration method based on the consideration of reducing the loading area and the space of the sand soil.The author made calibration tests in sand soil for three different sale earth pressure cells by using two different methods:The rigid loading and stress concentration method,and draw calibration curves of methods A,B and gas pressure calibration based on the results of two above methods and the manufacturer’s gas calibration results.In order to judge the advantages and disadvantages of the three calibration methods,the author compared the goodness of fit,calibration parameter and dispersion rate of data of the results of two methods and the gas calibration.The result shows that the linear correlation coefficients of stress concentration method’s calibration curves are all greater than 0.99,which means the calibration curves obtained by the new test method all have a low dispersion rate,so the its calibration results meet the accuracy requirements of the indoor test and have field application value.But the calibration coefficients of two sand pressure calibration method are significantly different from the gas pressure calibration method,which proves the existing of the soil arching during the earth cells working in the sand soil and the necessary to make a sand pressure calibration test.It is found that the calibration parameter of the rigid loading test is smaller than that of the gas standard but the calibration parameter of the stress concentration method is larger,which indicates that people can reduce the effect of soil arching and lateral stress on the sensor by reducing the soil space and the earth cell’s force area,so that make the stress on sensor surface more concentrated to avoid uneven distribution of stress.At last of the thesis,according to conclusions of test and analysis,the authors advice to use the stress concentration method as calibration tests of vibrating wire earth pressure cells in a soft sand environment with a large particle porosity.
作者
简筝
赵国彦
王玺
马举
肖屈日
JIAN Zheng;ZHAO Guoyan;WANG Xi;MA Ju;XIAO Quri(School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China;Deep Mining Laboratory Subsidiary of Shandong Gold Mining Technology Co.,Ltd.,Yantai 261400,Shandong,China)
出处
《黄金科学技术》
CSCD
2020年第4期541-549,共9页
Gold Science and Technology
基金
国家重点研发计划项目“深部金属矿绿色开采技术集成与示范”(编号:2018YFC0604606)资助。
关键词
振弦式土压力盒
土拱效应
流体标定方法
砂土标定方法
线性拟合
标定系数
vibrating wire earth pressure cells
soil arching
fluid pressure calibration method
sand pressure calibration method
linear fitting
calibration parameter
