一类三维土压力盒的设计及试验验证
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摘要
为测试土体内部一点的三维应力状态,基于常规应力状态与主应力之间的关系,给出了一类三维土压力盒的设计原理和制作方法。与普通土压力盒相比,该类三维土压力盒能测试空间一点完整的应力状态,即3个正应力和3个剪应力。该类装置均由1个特定基座和6个镶嵌于基座上的微型土压力盒组成。基座的形式可以多种多样,但根据6个土压力盒法线的方向余弦得到的转换矩阵必需是满秩的。考虑工程应用方面的要求,分别阐述3种三维土压力盒的制作方法和数据处理方法,并进行了误差和适用性分析。在一个模型槽内对某重塑土进行了压缩试验,分别用给出的3种三维土压力盒测试土中不同深度处的三维应力状态。研究结果表明:土体在一维侧限压力作用下,2个水平方向的正应力均小于竖向应力且与之具有线性关系;随着土体固结度的增加,外荷载引起的土体应力状态变化偏于平缓;采用分层密实方法制备的模型土体仍具备明显的各向异性,外荷载作用下土中的各向应力增量仍存在一定差异;侧限形式和外荷载大小是引起土体应力状态不同的主要因素,分层密实导致的土体初始各向异性在加载-卸载作用后趋于缓和;测得的竖向应力随深度增加逐渐减小,反映出随深度增加附加应力的扩散效应,从而初步证实该类测试装置是科学和可靠的。
In order to test the three-dimensional stress state in soil,the design principle and manufacturing method of three-dimensional earth pressure cells were given based on the relationship between the normal stress state and the principal stress.Compared with the common earth pressure cells,this kind of three-dimensional earth pressure cells could test the threedimensional stress state of the space,that is,three normal stresses and three shear stresses.The device was composed of a polyhedron base and 6 micro earth pressure cells,embedded on the base.The form of the base can be varied,but the transition matrix obtained from the directionalcosine of the 6 earth pressure cells' normal line must be non-singular.Considering the requirements of engineering application,the production methods and data processing methods on three kinds of three-dimensional earth pressure cells were described,whilst the error and applicability analysis were carried out.A compression test was carried out by the remolded soil in a rigid model box,and the three-dimensional stress state at different depths were tested by the three three-dimensional earth pressure cells.The results show that,the two horizontal normal stresses,less than the vertical stress,keep linear relationship with vertical stress under the onedimensional lateral confining pressure.With the increase of soil consolidation degree,the stress state of soil caused by external load tends to be slow.The model soil prepared by the layered compaction method presents obvious anisotropy,whilst there is still an obvious difference in the increment of stress in the soil under the external load.The lateral confining form and the external load level are the main factors that cause the different stress state of soil,and the initial anisotropy caused by layered compaction method tends to be isotropic after the loading-unloading process.The measured vertical stress gradually decreases with the increase of depth,which reflects the diffusion effect of additional stress with depth.It is proved that this kind of test device is scientific and reliable.
In order to test the three-dimensional stress state in soil,the design principle and manufacturing method of three-dimensional earth pressure cells were given based on the relationship between the normal stress state and the principal stress.Compared with the common earth pressure cells,this kind of three-dimensional earth pressure cells could test the threedimensional stress state of the space,that is,three normal stresses and three shear stresses.The device was composed of a polyhedron base and 6 micro earth pressure cells,embedded on the base.The form of the base can be varied,but the transition matrix obtained from the directionalcosine of the 6 earth pressure cells' normal line must be non-singular.Considering the requirements of engineering application,the production methods and data processing methods on three kinds of three-dimensional earth pressure cells were described,whilst the error and applicability analysis were carried out.A compression test was carried out by the remolded soil in a rigid model box,and the three-dimensional stress state at different depths were tested by the three three-dimensional earth pressure cells.The results show that,the two horizontal normal stresses,less than the vertical stress,keep linear relationship with vertical stress under the onedimensional lateral confining pressure.With the increase of soil consolidation degree,the stress state of soil caused by external load tends to be slow.The model soil prepared by the layered compaction method presents obvious anisotropy,whilst there is still an obvious difference in the increment of stress in the soil under the external load.The lateral confining form and the external load level are the main factors that cause the different stress state of soil,and the initial anisotropy caused by layered compaction method tends to be isotropic after the loading-unloading process.The measured vertical stress gradually decreases with the increase of depth,which reflects the diffusion effect of additional stress with depth.It is proved that this kind of test device is scientific and reliable.
引文
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[10]王丽丽,忻向军,郝金光.基于光纤光栅的结构体裂缝三维应变传感[J].光子学报,2016,45(12):7-11.WANG Li-li,XIN Xiang-jun,HAO Jin-guang.Mechanism of Three-dimension Sensing with Fiber Gratings for Structure Cracks Detection[J].Acta Photonica Sinica,2016,45(12):7-11.
[11]李顺群,高凌霞,冯慧强,等.一种接触式三维应变花的工作原理及其应用[J].岩土力学,2015,36(5):1513-1520.LI Shun-qun,GAO Ling-xia,FENG Hui-qiang,et al.Principle and Application of a Three-dimensional Contacting Strain Rosette[J].Rock and Soil Mechanics,2015,36(5):1513-1520.
[12]张坤勇.考虑应力各向异性土体本构模型及其应用研究[D].南京:河海大学,2004.ZHANG Kun-yong.Study and Application on Soil’s Constitutive Model with the Consideration of Stress-induced Anisotropy[D].Nanjing:Hohai University,2004.
[13]江强,朱建明,姚仰平.基于SMP准则的土体三维应力状态土压力问题[J].岩土工程学报,2006,28(增):1415-1417.JIANG Qiang,ZHU Jian-ming,YAO Yang-ping.Earth Pressure of Three-dimensional Soil Stress States Based on SMP Failure Criterion[J].Chinese Journal of Geotechnical Engineering,2006,28(S):1415-1417.
[14]沈珠江.土的弹塑性应力-应变关系的合理形式[J].岩土工程学报,1980,2(2):11-19.SHEN Zhu-jiang.The Rational Form of Stress-strain Relationship of Soils Based on Elastic-plasticity Theory[J].Chinese Journal of Geotechnical Engineering,1980,2(2):11-19.
[15]张彬,王钊,杨俊峰,等.土压力盒在工程应用中的误差分析[J].探矿工程,2005(增):157-161.ZHANG Bin,WANG Zhao,YANG Jun-feng,et al.Error Analyses of Application of Earth Pressure Cell in Geotechnical Engineering[J].Exploration Engineering,2005(S):157-161.
[16]曾辉,余尚江.岩土压力传感器匹配误差的计算[J].岩土力学,2001,22(1):99-105.ZENG Hui,YU Shang-jiang.The Calculation of Matching Error of Rock-earth Pressure Transducer[J].Rock and Soil Mechanics,2001,22(1):99-105.
[17]刘先珊,董存军.砂土介质中土压力盒的力学响应特性[J].土木建筑与环境工程,2012,34(4):12-18.LIU Xian-shan,DONG Cun-jun.Mechanical Response Characteristics of the Earth Pressure Cell in Sand[J].Journal of Civil Architectural&Environment Engineering,2012,34(4):12-18.
[18]天津城建大学.侧向位移式多功能模型槽实验系统:中国,201410022445.X[P].2015-07-15.Tianjin Chengjian University.Lateral Displacement Multi-function Model Experiment System:China,201410022445.X[P].2015-07-15.
[2]陈祥,孙进忠,蔡新滨.基桩水平静载试验及内力和变形分析[J].岩土力学,2010,31(3):753-759.CHEN Xiang,SUN Jin-zhong,CAI Xin-bin.Horizontal Static Loading Test and Analyses of Internal Force and Distortion on Single Pile[J].Rock and Soil Mechanics,2010,31(3):753-759.
[3]LABUZ J F,THEROUX B.Laboratory Calibration of Earth Pressure Cells[J].Geotechnical Testing Journal,2005,28(2):188-196.
[4]陈春红,刘素锦,王钊.土压力盒的标定[J].中国农村水利水电,2007(2):29-33.CHEN Chun-hong,LIU Su-jin,WANG Zhao.Calibration of Earth Pressure Cell[J].China Rural Water and Hydropower,2007(2):29-33.
[5]WANG S H,ZUO D W,WANG M,et al.Modified Layer Removal Method for Measurement of Residual Stress Distribution in Thick Pre-stretched Aluminum Plate[J].Transactions of Nanjing University of Aeronautics&Astronautics,2004,21(4):286-290.
[6]钱建固,黄茂松.复杂应力状态下岩土体的非共轴塑性流动理论[J].岩石力学与工程学报,2006,25(6):1259-1264.QIAN Jian-gu,HUANG Mao-song.Non-coaxial Plastic Flow Theory in Multi-dimensional Stress Space[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(6):1259-1264.
[7]路德春,姚仰平,周安楠.土体平面应变条件下的主应力关系[J].岩石力学与工程学报,2006,25(11):2320-2326.LU De-chun,YAO Yang-ping,ZHOU An-nan.Relationship Between Principal Stresses of Soil Mass Under Plane Strain Condition[J].Chinese Journal of Rock Mechanics and Engineering,2006,25(11):2320-2326.
[8]张芳,刘泉声,张程远,等.流变应力恢复法地应力测试及装置[J].岩土力学,2014,35(5):1506-1513.ZHANG Fang,LIU Quan-sheng,ZHANG Chengyuan,et al.Geostress Measurement Using Rheological Stress Recovery Method and Its Equipment[J].Rock and Soil Mechanics,2014,35(5):1506-1513.
[9]张宏,李顺群,张少峰,等.三维应力计的工作原理及误差分析[J].土木建筑与环境工程,2015,37(5):54-59.ZHANG Hong,LI Shun-qun,ZHANG Shao-feng,et al.Principle and Errors Analysis of the Three-dimensional Stress Apparatuses[J].Journal of Civil,Architectural&Environmental Engineering,2015,37(5):54-59.
[10]王丽丽,忻向军,郝金光.基于光纤光栅的结构体裂缝三维应变传感[J].光子学报,2016,45(12):7-11.WANG Li-li,XIN Xiang-jun,HAO Jin-guang.Mechanism of Three-dimension Sensing with Fiber Gratings for Structure Cracks Detection[J].Acta Photonica Sinica,2016,45(12):7-11.
[11]李顺群,高凌霞,冯慧强,等.一种接触式三维应变花的工作原理及其应用[J].岩土力学,2015,36(5):1513-1520.LI Shun-qun,GAO Ling-xia,FENG Hui-qiang,et al.Principle and Application of a Three-dimensional Contacting Strain Rosette[J].Rock and Soil Mechanics,2015,36(5):1513-1520.
[12]张坤勇.考虑应力各向异性土体本构模型及其应用研究[D].南京:河海大学,2004.ZHANG Kun-yong.Study and Application on Soil’s Constitutive Model with the Consideration of Stress-induced Anisotropy[D].Nanjing:Hohai University,2004.
[13]江强,朱建明,姚仰平.基于SMP准则的土体三维应力状态土压力问题[J].岩土工程学报,2006,28(增):1415-1417.JIANG Qiang,ZHU Jian-ming,YAO Yang-ping.Earth Pressure of Three-dimensional Soil Stress States Based on SMP Failure Criterion[J].Chinese Journal of Geotechnical Engineering,2006,28(S):1415-1417.
[14]沈珠江.土的弹塑性应力-应变关系的合理形式[J].岩土工程学报,1980,2(2):11-19.SHEN Zhu-jiang.The Rational Form of Stress-strain Relationship of Soils Based on Elastic-plasticity Theory[J].Chinese Journal of Geotechnical Engineering,1980,2(2):11-19.
[15]张彬,王钊,杨俊峰,等.土压力盒在工程应用中的误差分析[J].探矿工程,2005(增):157-161.ZHANG Bin,WANG Zhao,YANG Jun-feng,et al.Error Analyses of Application of Earth Pressure Cell in Geotechnical Engineering[J].Exploration Engineering,2005(S):157-161.
[16]曾辉,余尚江.岩土压力传感器匹配误差的计算[J].岩土力学,2001,22(1):99-105.ZENG Hui,YU Shang-jiang.The Calculation of Matching Error of Rock-earth Pressure Transducer[J].Rock and Soil Mechanics,2001,22(1):99-105.
[17]刘先珊,董存军.砂土介质中土压力盒的力学响应特性[J].土木建筑与环境工程,2012,34(4):12-18.LIU Xian-shan,DONG Cun-jun.Mechanical Response Characteristics of the Earth Pressure Cell in Sand[J].Journal of Civil Architectural&Environment Engineering,2012,34(4):12-18.
[18]天津城建大学.侧向位移式多功能模型槽实验系统:中国,201410022445.X[P].2015-07-15.Tianjin Chengjian University.Lateral Displacement Multi-function Model Experiment System:China,201410022445.X[P].2015-07-15.
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