堆石料干密度缩尺效应与制样标准研究
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摘要
针对已有相对密度试验成果仅限于室内试验的现状,采用某工程花岗岩堆石料,首次进行现场大尺寸密度桶试验,研究不同缩尺方法对干密度试验结果的影响,研究干密度缩尺效应对于室内缩尺试验的制样标准以及现场压实质量评价的影响。结果表明:(1)由于缩尺后级配的截尾误差、颗粒形状差异等因素,即使采用相似级配法缩尺,堆石料干密度也随着最大粒径的增大而增大,仍然存在一定的缩尺效应;但当最大粒径达到300mm以上时,这种缩尺效应显著减小;(2)最大粒径不同的各组级配堆石料干密度测量值均存在极大值,对应的临界分形维数与级配的最大粒径无关;(3)目前普遍使用的混合缩尺方法,降低了原级配堆石料的粒度分形维数,劣化了颗粒之间的充填关系,导致同一相对密度条件下的干密度比相似级配法的试验结果更明显偏离现场,难以合理反映原级配堆石料的物理力学性质;(4)采用与现场碾压堆石体相同的相对密度标准制样,比直接采用现场填筑干密度制样,其室内压缩试验得到的压缩模量降低90%～220%;不考虑干密度缩尺效应的室内试验结果,大大高估了现场碾压堆石体的力学性质;(5)采用室内试验结果直接计算现场原级配堆石体的相对密度,高估了堆石体的压实程度,甚至可能出现相对密度大于1的问题。
In view of the current situation that the relative density test results are limited to indoor tests,site large-scale density barrel tests were carried out on granite rockfill material from a certain engineering for the first time. The effect of different scale methods on the dry density was investigated,and the influence of the dry density scale effect on the sample preparation standards for indoor scale tests and on-site compaction quality evaluation was revealed. The test results show that,due to the truncation error of the grading after the scale and the difference of the particle shape,the dry density of the rockfill increases with increasing the maximum particle size and the scale effect still exists even if the similar scale is used,but that the scale effect is significantly reduced when the maximum particle size reaches 300 mm or more. The measured dry density of each group of grading piles with different maximum particle diameters have maximum values,and the corresponding critical fractal dimension has nothing to do with the maximum particle size of the gradation. the mixed scale method commonly used at present reduces the fractal dimension of the original graded rockfill and deteriorates the filling relationship between the particles,and as a result,the dry density under the same relative density condition deviates from the scene more obviously than the test result of the similar grading method which is difficult to reasonably reflect the physical and mechanical properties of the original graded rockfill. It is shown that,using the same relative density standard sample preparation as the on-site compacted rockfill body,the compression modulus obtained by the indoor compression test is reduced by 90%–220% compared with the direct filling of the dry density sample on site and that the indoor test results without considering the density scale effect significantly overestimate the mechanical properties of the rockfill on site. The indoor test results used to directly calculate the relative density of the original graded rockfill body overestimate the compaction degree of the rockfill body,and even the calculation value of the relative density may be greater than 1.
In view of the current situation that the relative density test results are limited to indoor tests,site large-scale density barrel tests were carried out on granite rockfill material from a certain engineering for the first time. The effect of different scale methods on the dry density was investigated,and the influence of the dry density scale effect on the sample preparation standards for indoor scale tests and on-site compaction quality evaluation was revealed. The test results show that,due to the truncation error of the grading after the scale and the difference of the particle shape,the dry density of the rockfill increases with increasing the maximum particle size and the scale effect still exists even if the similar scale is used,but that the scale effect is significantly reduced when the maximum particle size reaches 300 mm or more. The measured dry density of each group of grading piles with different maximum particle diameters have maximum values,and the corresponding critical fractal dimension has nothing to do with the maximum particle size of the gradation. the mixed scale method commonly used at present reduces the fractal dimension of the original graded rockfill and deteriorates the filling relationship between the particles,and as a result,the dry density under the same relative density condition deviates from the scene more obviously than the test result of the similar grading method which is difficult to reasonably reflect the physical and mechanical properties of the original graded rockfill. It is shown that,using the same relative density standard sample preparation as the on-site compacted rockfill body,the compression modulus obtained by the indoor compression test is reduced by 90%–220% compared with the direct filling of the dry density sample on site and that the indoor test results without considering the density scale effect significantly overestimate the mechanical properties of the rockfill on site. The indoor test results used to directly calculate the relative density of the original graded rockfill body overestimate the compaction degree of the rockfill body,and even the calculation value of the relative density may be greater than 1.
引文
[1]中华人民共和国行业标准编写组.DLT 5016-2011混凝土面板堆石坝设计规范[S].[S.l.]:[s.n.],2011.(The Professional Standards Compilation Group of the People′s Republic of China.DLT5016-2011 Design code for concrete face rockfill dams[S].[S.l.]:[s.n.],2011.(in Chinese))
[2]MARSAL R J.Mechanical properties of rockfill[C]//EmbankmentDam Engineering,Casagrande Volum.New York:Wiley,1973:109-200.
[3]朱晟,钟春欣,郑希镭,等.堆石体的填筑标准与级配优化研究[J].岩土工程学报,2018,40(1):108-115.(ZHU Sheng,ZHONGChunxin,ZHENG Xilei,et al.Filling standards and gradation optimization of rockfill materials[J].Chinese Journal of Geotechnical Engineering,2018,40(1):108-115.(in Chinese))
[4]史彦文.大粒径粗粒坝料填筑标准的确定及施工控制[J].岩土工程学报,1982,4(4):78-93.(SHI Yanwen.Determination of filling criteria of large grain-size coarse materials for dam and construction control[J].Chinese Journal of Geotechnical Engineering,1982,4(4):78-93.(in Chinese))
[5]冯冠庆,杨荫华.堆石料最大指标密度室内试验方法的研究[J].岩土工程学报,1992,14(5):37-45.(FENG Quanqing,YANG Yinhua.Laboratory test methods for maximum index density of rockfill materials[J].Chinese Journal of Geotechnical Engineering,1992,14(5):37-45.(in Chinese))
[6]田树玉.用渐近线辅助拟合法确定大粒径砂卵石最大干容重[J].岩土工程学报,1992,14(1):35-43.(TIAN Shuyu.Determining the max.dry density of coarse grained sandy gravels by the method of curve-fitting with asymptotic line[J].Chinese Journal of Geotechnical Engineering,1992,14(1):35-43.(in Chinese))
[7]朱俊高,翁厚洋,吴晓铭,等.粗粒料级配缩尺后压实密度试验研究[J].岩土力学,2010,31(8):2 394-2 398.(ZHU Jungao,WENGHouyang,WU Xiaoming,et al.Experimental study of compact density of scaled coarse-grained soil[J].Rock and Soil Mechanics,2010,31(8):2 394-2 398.(in Chinese))
[8]傅华,韩华强,凌华.堆石料级配缩尺方法对其室内试验结果的影响[J].岩土力学,2012,33(9):2 645-2 649.(FU Hua,HANHuaqiang,LING Hua.Effect of grading scale method on results of laboratory tests on rockfill materials[J].Rock and Soil Mechanics,2012,33(9):2 645-2 649.(in Chinese))
[9]朱晟,王永明,翁厚洋.粗粒筑坝材料密实度的缩尺效应研究[J].岩石力学与工程学报,2011,30(2):348-357.(ZHU Sheng,WANGYongming,WENG Houyang.Study of scale effect of density of coarse-trained dam materials[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(2):348-357.(in Chinese))
[10]王永明,朱晟,任金明,等.筑坝粗粒料力学特性的缩尺效应研究[J].岩土力学,2013,34(6):1 799-1 806.(WANG Yongming,ZHU Sheng,REN Jinming,et al.Research on scale effect of coarse-grained materials[J].Rock and Soil Mechanics,2013,34(6):1 799-1 806.(in Chinese))
[11]赵娜,左永振,王占彬,等.基于分形理论的粗粒料级配缩尺方法研究[J].岩土力学,2016,37(12):3 513-3 519.(ZHAO Na,ZUOYongzhen,WANG Zhanbin,et al.Grading scale method for coarse-grained soils based on fractal theory[J].Rock and Soil Mechanics,2016,37(12):3 513-3 519.(in Chinese))
[12]武利强,朱晟,章晓桦,等.粗粒料试验缩尺效应的分析研究[J].岩土力学,2016,37(8):2 187-2 197.(WU Liqiang,ZHU Sheng,ZHANGXiaohua,et al.Analysis of scale effect of coarse-grained materials[J].Rock and Soil Mechanics,2016,37(8):2 187-2 197.(in Chinese))
[13]中华人民共和国行业标准编写组.NB/T 35016-2013土石筑坝材料碾压试验规程[S].[S.l.]:[s.n.],2013.(The Professional Standards Compilation Group of the People′s Republic of China.NB/T 35 016-2 013 Specification for rolling test of materials for earth and rockfill dams[S].[S.l.]:[s.n.],2013.(in Chinese))
[14]中华人民共和国行业标准编写组.DLT 5356-2006水电水利工程粗粒土试验规程[S].[S.l.]:[s.n.],2006.(The Professional Standards Compilation Group of the People′s Republic of China.DLT 5356-2006 Test code for coarse grained soil in hydropower and water conservancy projects[S].[S.l.]:[s.n.],2006.(in Chinese))
[15]朱晟.一种确定粗粒料室内缩尺试验相对密度制样标准的方法与试验装置[P].中国:ZL 20151067446.8,2017-09-29.(ZHUSheng.Method and test device for determining relative density sample preparation standard for coarse-grained indoor scale test[P].China:ZL20151067446.8,2017-09-29.(in Chinese))
[16]朱晟,邓石德,宁志远,等.基于分形理论的堆石料级配设计方法[J].岩土工程学报,2017,39(6):1 151-1 155.(ZHU Sheng,DENG Shide,NING Zhiyuan,et al.Gradation design method of rockfill materials based on the fractal theory[J].Chinese Journal of Geotechnical Engineering,2017,39(6):1 151-1 155.(in Chinese))
[17]YOUD T L.Factors CONTROLLING MAXIMUM AND MINIMUMDENSITIES OF SANDS[C]//Seventy-fifth Annual Meeting of ASTM.Los Angeles:ASTM.1972:98-112.
[18]NAKATA Y,KATO Y,HYODO M,et al.One dimensional compression behaviour of uniformly graded sand related to single particle crushing strength[J].Soils and Foundations,2001,41(2):39-51.
[2]MARSAL R J.Mechanical properties of rockfill[C]//EmbankmentDam Engineering,Casagrande Volum.New York:Wiley,1973:109-200.
[3]朱晟,钟春欣,郑希镭,等.堆石体的填筑标准与级配优化研究[J].岩土工程学报,2018,40(1):108-115.(ZHU Sheng,ZHONGChunxin,ZHENG Xilei,et al.Filling standards and gradation optimization of rockfill materials[J].Chinese Journal of Geotechnical Engineering,2018,40(1):108-115.(in Chinese))
[4]史彦文.大粒径粗粒坝料填筑标准的确定及施工控制[J].岩土工程学报,1982,4(4):78-93.(SHI Yanwen.Determination of filling criteria of large grain-size coarse materials for dam and construction control[J].Chinese Journal of Geotechnical Engineering,1982,4(4):78-93.(in Chinese))
[5]冯冠庆,杨荫华.堆石料最大指标密度室内试验方法的研究[J].岩土工程学报,1992,14(5):37-45.(FENG Quanqing,YANG Yinhua.Laboratory test methods for maximum index density of rockfill materials[J].Chinese Journal of Geotechnical Engineering,1992,14(5):37-45.(in Chinese))
[6]田树玉.用渐近线辅助拟合法确定大粒径砂卵石最大干容重[J].岩土工程学报,1992,14(1):35-43.(TIAN Shuyu.Determining the max.dry density of coarse grained sandy gravels by the method of curve-fitting with asymptotic line[J].Chinese Journal of Geotechnical Engineering,1992,14(1):35-43.(in Chinese))
[7]朱俊高,翁厚洋,吴晓铭,等.粗粒料级配缩尺后压实密度试验研究[J].岩土力学,2010,31(8):2 394-2 398.(ZHU Jungao,WENGHouyang,WU Xiaoming,et al.Experimental study of compact density of scaled coarse-grained soil[J].Rock and Soil Mechanics,2010,31(8):2 394-2 398.(in Chinese))
[8]傅华,韩华强,凌华.堆石料级配缩尺方法对其室内试验结果的影响[J].岩土力学,2012,33(9):2 645-2 649.(FU Hua,HANHuaqiang,LING Hua.Effect of grading scale method on results of laboratory tests on rockfill materials[J].Rock and Soil Mechanics,2012,33(9):2 645-2 649.(in Chinese))
[9]朱晟,王永明,翁厚洋.粗粒筑坝材料密实度的缩尺效应研究[J].岩石力学与工程学报,2011,30(2):348-357.(ZHU Sheng,WANGYongming,WENG Houyang.Study of scale effect of density of coarse-trained dam materials[J].Chinese Journal of Rock Mechanics and Engineering,2011,30(2):348-357.(in Chinese))
[10]王永明,朱晟,任金明,等.筑坝粗粒料力学特性的缩尺效应研究[J].岩土力学,2013,34(6):1 799-1 806.(WANG Yongming,ZHU Sheng,REN Jinming,et al.Research on scale effect of coarse-grained materials[J].Rock and Soil Mechanics,2013,34(6):1 799-1 806.(in Chinese))
[11]赵娜,左永振,王占彬,等.基于分形理论的粗粒料级配缩尺方法研究[J].岩土力学,2016,37(12):3 513-3 519.(ZHAO Na,ZUOYongzhen,WANG Zhanbin,et al.Grading scale method for coarse-grained soils based on fractal theory[J].Rock and Soil Mechanics,2016,37(12):3 513-3 519.(in Chinese))
[12]武利强,朱晟,章晓桦,等.粗粒料试验缩尺效应的分析研究[J].岩土力学,2016,37(8):2 187-2 197.(WU Liqiang,ZHU Sheng,ZHANGXiaohua,et al.Analysis of scale effect of coarse-grained materials[J].Rock and Soil Mechanics,2016,37(8):2 187-2 197.(in Chinese))
[13]中华人民共和国行业标准编写组.NB/T 35016-2013土石筑坝材料碾压试验规程[S].[S.l.]:[s.n.],2013.(The Professional Standards Compilation Group of the People′s Republic of China.NB/T 35 016-2 013 Specification for rolling test of materials for earth and rockfill dams[S].[S.l.]:[s.n.],2013.(in Chinese))
[14]中华人民共和国行业标准编写组.DLT 5356-2006水电水利工程粗粒土试验规程[S].[S.l.]:[s.n.],2006.(The Professional Standards Compilation Group of the People′s Republic of China.DLT 5356-2006 Test code for coarse grained soil in hydropower and water conservancy projects[S].[S.l.]:[s.n.],2006.(in Chinese))
[15]朱晟.一种确定粗粒料室内缩尺试验相对密度制样标准的方法与试验装置[P].中国:ZL 20151067446.8,2017-09-29.(ZHUSheng.Method and test device for determining relative density sample preparation standard for coarse-grained indoor scale test[P].China:ZL20151067446.8,2017-09-29.(in Chinese))
[16]朱晟,邓石德,宁志远,等.基于分形理论的堆石料级配设计方法[J].岩土工程学报,2017,39(6):1 151-1 155.(ZHU Sheng,DENG Shide,NING Zhiyuan,et al.Gradation design method of rockfill materials based on the fractal theory[J].Chinese Journal of Geotechnical Engineering,2017,39(6):1 151-1 155.(in Chinese))
[17]YOUD T L.Factors CONTROLLING MAXIMUM AND MINIMUMDENSITIES OF SANDS[C]//Seventy-fifth Annual Meeting of ASTM.Los Angeles:ASTM.1972:98-112.
[18]NAKATA Y,KATO Y,HYODO M,et al.One dimensional compression behaviour of uniformly graded sand related to single particle crushing strength[J].Soils and Foundations,2001,41(2):39-51.
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