路基黄土强度特性与地基承载力研究
|
摘要
本文以路基黄土为研究对象,以直剪试验、三轴试验、载荷试验和电镜扫描试验为主要手段,对压实前后路基黄土的微观结构、抗剪强度、地基承载力等特性进行了系统的试验研究和深入的理论分析,对预防和治理黄土路基的地质灾害有着重要的实际意义。本文的研究工作和主要成果如下:
首先,对压实前后的土样做了颗粒分析和电镜扫描观察,对比分析了压实前后黄土的粒度组成、孔隙特征和微结构类型的变化,得知压实后黄土中集粒、块粒表面胶结物剥落,颗粒变细,大孔隙减少,原始颗粒骨架破坏,微结构类型由絮凝状微胶结结构和支架大孔微胶结结构变为镶嵌结构和叠置结构。
其次,对路基黄土进行了直剪、无侧限抗压强度与三轴压缩、单轴高压固结等试验。分析了原状黄土与压实黄土强度参数(c、φ)的影响因素及变化规律,建立了用含水量表示的抗剪强度公式;利用软化系数表现了水对路基黄土无侧限抗压强度的影响;研究了路基黄土三轴试验条件下的应力一应变特征、应力路径及剪切破坏型式,探讨了路基黄土Et-μt模型。
最后,对原状黄土与强夯、振动碾压、冲击碾压不同处治方案下的压实黄土地基承载力采用了载荷试验、动力触探、标准贯入、静力触探等手段进行检测。通过回归分析得出了一般新黄土的容许承载力与物理指标之间的相关关系,编制了一般新黄土地基承载力表,该成果为《公路桥涵地基与基础设计规范》的修订提供了可靠的依据,具有很高的实用价值。通过对载荷试验与单轴高压固结试验条件下路基黄土的应力—应变曲线与时间—沉降曲线特征分析,探讨了路基土体的强度变形特征。通过对各处治方案下路基黄土的压实度、抗剪强度与地基极限承载力比较分析,提出了黄土路基有效的施工处治方案。通过对地基承载力不同的检测手段对比分析,指出了合理有效的检测方法。
Focus on the subgrade loess, by main means of direct shear test, triaxial test, load test and Scanning electric microscope (SEM) test, this paper carries systemic trial research and thorough theories analysis on its characteristics including microstructure, shear strength, ground bearing capacity and so on of the intact loess and the compacted loess. It is of great significance in preventing and dealing with the geological disasters of the loess subgrade. The studies and main fruits as follows:
Firstly, changes of the particulate components, pore characteristic and microstructure of the intact loess and the compacted loess are contrasted by the way of grain-analysis and SEM. From the analysis and observation, it could be seen that the surface cementation of conglomeration peels, grain becomes thinner; the original grain framework of the loess is destroyed, the flocculate cline-cementation structure and plank-macrospore cline-cementation structure turns to be embedded structure and pile-up structure.
Secondly, a series of subgrade loess tests were carried out under direct shear, unconfined compressive strength test, triaxial test and monopodium compression test. The change rules and the influence factor of parameter of shear strength are analyzed. Then the formulae of the shear strength are established with water contend. The effect to unconfined compressive strength of subgrade loess by water was manifested utilizing softening coefficient. And then the character of stress strain, stress path, shear failture model on the triaxialtest are studied. E_t -μ_t model of subgrade loess is discussed.
Finally, the load test, power touch scout, standard enter, static touch scout and other detection methods are adopted for studying compacted loess ground bearing capacity in different deal schemes including strong tamper, vibration grinding press, striking grinding press and the intact loess. The correlativity between allowable bearing capacity and physics Index of neo loess is elicited through regression analysis, and the table of allowable bearing capacity of the neo loess is worked out The fruits provide reliable basis for edition of "Specifications for Design of Ground Base and Foundation of Highway Bridges and Culverts". The character of stress deformation is discussed through analyzing traits of load deformation curve and time-settlement curve on load test and monopodium compression test. Based comparison analysis of the degree of compaction , shear strength, ultimate bearing capacity of various processing schemes, the effective processing schemes of construction are put forward. On contrast analysis of various detection methods of ground bearing capacity, the reasonable and effective detection methods of ground bearing capacity are brought forward.
首先,对压实前后的土样做了颗粒分析和电镜扫描观察,对比分析了压实前后黄土的粒度组成、孔隙特征和微结构类型的变化,得知压实后黄土中集粒、块粒表面胶结物剥落,颗粒变细,大孔隙减少,原始颗粒骨架破坏,微结构类型由絮凝状微胶结结构和支架大孔微胶结结构变为镶嵌结构和叠置结构。
其次,对路基黄土进行了直剪、无侧限抗压强度与三轴压缩、单轴高压固结等试验。分析了原状黄土与压实黄土强度参数(c、φ)的影响因素及变化规律,建立了用含水量表示的抗剪强度公式;利用软化系数表现了水对路基黄土无侧限抗压强度的影响;研究了路基黄土三轴试验条件下的应力一应变特征、应力路径及剪切破坏型式,探讨了路基黄土Et-μt模型。
最后,对原状黄土与强夯、振动碾压、冲击碾压不同处治方案下的压实黄土地基承载力采用了载荷试验、动力触探、标准贯入、静力触探等手段进行检测。通过回归分析得出了一般新黄土的容许承载力与物理指标之间的相关关系,编制了一般新黄土地基承载力表,该成果为《公路桥涵地基与基础设计规范》的修订提供了可靠的依据,具有很高的实用价值。通过对载荷试验与单轴高压固结试验条件下路基黄土的应力—应变曲线与时间—沉降曲线特征分析,探讨了路基土体的强度变形特征。通过对各处治方案下路基黄土的压实度、抗剪强度与地基极限承载力比较分析,提出了黄土路基有效的施工处治方案。通过对地基承载力不同的检测手段对比分析,指出了合理有效的检测方法。
Focus on the subgrade loess, by main means of direct shear test, triaxial test, load test and Scanning electric microscope (SEM) test, this paper carries systemic trial research and thorough theories analysis on its characteristics including microstructure, shear strength, ground bearing capacity and so on of the intact loess and the compacted loess. It is of great significance in preventing and dealing with the geological disasters of the loess subgrade. The studies and main fruits as follows:
Firstly, changes of the particulate components, pore characteristic and microstructure of the intact loess and the compacted loess are contrasted by the way of grain-analysis and SEM. From the analysis and observation, it could be seen that the surface cementation of conglomeration peels, grain becomes thinner; the original grain framework of the loess is destroyed, the flocculate cline-cementation structure and plank-macrospore cline-cementation structure turns to be embedded structure and pile-up structure.
Secondly, a series of subgrade loess tests were carried out under direct shear, unconfined compressive strength test, triaxial test and monopodium compression test. The change rules and the influence factor of parameter of shear strength are analyzed. Then the formulae of the shear strength are established with water contend. The effect to unconfined compressive strength of subgrade loess by water was manifested utilizing softening coefficient. And then the character of stress strain, stress path, shear failture model on the triaxialtest are studied. E_t -μ_t model of subgrade loess is discussed.
Finally, the load test, power touch scout, standard enter, static touch scout and other detection methods are adopted for studying compacted loess ground bearing capacity in different deal schemes including strong tamper, vibration grinding press, striking grinding press and the intact loess. The correlativity between allowable bearing capacity and physics Index of neo loess is elicited through regression analysis, and the table of allowable bearing capacity of the neo loess is worked out The fruits provide reliable basis for edition of "Specifications for Design of Ground Base and Foundation of Highway Bridges and Culverts". The character of stress deformation is discussed through analyzing traits of load deformation curve and time-settlement curve on load test and monopodium compression test. Based comparison analysis of the degree of compaction , shear strength, ultimate bearing capacity of various processing schemes, the effective processing schemes of construction are put forward. On contrast analysis of various detection methods of ground bearing capacity, the reasonable and effective detection methods of ground bearing capacity are brought forward.
引文
[1]王永焱,林在贯等.中国黄土的结构特征及物理力学性质[M].北京:科学出版社,1990:2
[2]乔平定,李增均.黄土地区工程地质[M].北京:水利水电出版社,1990:3
[3]Hu,R.L.etc,Mechanical behavior and microstructural variation of loess under dynamic compaction,Engineering Geology,v 59,n 3-4,April,2001,p 203-217
[4]Bowders,John J.Shear behavior of compacted silty loess,Geotechnical Special Publication,n 99,2000,p 235-246
[5]Li,Z.M,Compressibility and collapsibility of compacted unsaturated loessial soils,Proc 1995 1 Int Conf Unsaturated Soils,v 1,1995,p 139
[6]Rabinovich,I.G.etc,Features of deformations of the rammed collapsible soils,Proceedings of the International Conference on Soil Mechanics and Foundation Engineering,v 1,Deformation of Soils and Displacements of Structures X ECSMFE,1991,p 157-158
[7]Minkov,M.etc,Compaction and stabilization of loess in Bulgaria.Proceedings of the International Conference on Soil Mechanics and Foundation Engineering,v 3,1981,p 745-748
[8]Sneddon,Roy V,Stress-strain characterization of two compacted soil,Transportation Research Record,n 548,1975,p 97-103
[9]张宗祜.我国黄土类土显微结构的研究[J].地质学报,1964,44(3):357-364
[10]刘东生.中国黄土的地质环境[J].科学通报,1978,23(1):1-9
[11]高国瑞.黄土显微结构分类与湿陷性[J].中国科学,1980(12):1203-1208
[12]王永焱,林在贯等.中国黄土的结构特征及物理力学性质[M].北京:科学出版社,1990:157-158
[13]雷祥义.中国黄土的孔隙类型与湿陷性[J].中国科学(B辑),1987(12):1309-1316
[14]白晓红,山西潞城黄土的工程特性,岩土工程学报[J],2002,24(4):516-518
[15]谢定义,齐吉琳.土结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656
[16]齐吉琳,谢定义,石玉成.土结构性的研究方法及现状[J].西北地震学报,2001,23(1):99-102
[17]邵生俊,周飞飞,龙吉勇.原状黄土结构性及其定量化参数研究[J].岩土工程学报,2004,26(4):531-536
[18]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社,1997:115-127
[19]苗天德等.考虑微结构失稳的湿陷性黄土变形机理[J].中国科学(B辑).1990,(1):86-96
[20]Miao T D,Wang Z G..Deformation mechanism of collapsible loess in consideration of the miceostructure instability.Catern Suppl,1991,20:93-105
[21]苗天德等.湿陷性黄土的变形机理与本构关系[J].岩土工程学报.1999,21(4):383-387
[22]杨代泉.非饱和土弹塑性应力应变特性模拟[J].岩土工程学报,1995,17(6):42-49
[23]陈正汉,黄海,卢再华.非饱和土的非线性固结模型与弹塑性固结模型及其应用[J].应用数学与力学,2001,22(1):93-103
[24]景宏君,张斌.黄土路基强度规律.交通运输工程学报[J].2004,4(2):14-18
[25]刘建民.从压实土体的强度特征看黄土的现场压实控制[J].工业建筑.1994,24(10):26-30
[26]杨有海,王丽琴,苏在朝等.重塑黄土的强度特性及其影响因素的研究[J].兰州铁道学院学报.2003,22(3):38-41
[27]胡瑞林,李焯芬,王思敬,等.动荷载作用下黄土的强度特征及结构变化机理研究[J].岩土工程学报.2000,22(2):174-178
[28]胡瑞林,王思敬,李向全,等.模拟强夯下黄土的固结变形特征及其微观分析[J].岩土力学.1999,20(4):12-17
[29]李晓军,张登良.CT技术在土体结构性分析中的应用初探[J].岩土力学.1999,20(2):62-66
[30]李晓军,张登良.路基填土单轴受压细观结构CT监测分析[J].岩土工程学报.2000,22(2):205-209
[31]张玉蕴.黄土微结构研究的回顾与探讨[J].工程建设与设计,2004,(5):10-11
[32]卢肇钧,张惠明,陈建华,等.非饱和土的抗剪强度与膨胀压力[J].岩土工程学报,1992,14(3):1-8
[33]D.G.Fredlund,N.R.Morgenstern,R.A.Widger,The Shear Strength of Unsaturated Soils,Can.Geotech.J.,1978,15(3):313-321
[34]徐永福.非饱和膨胀土的力学特性及其工程应用[D].河海大学博士学位论文,1997
[35]缪林昌,仲晓晨,殷宗泽.膨胀土的强度与含水量的关系[J].岩土力学,1999,20(2):71-75
[36]关文章.湿陷性黄土工程性能新编[M].西安:西安交通大学出版社,1990:17-19
[37]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2002
[38]党进谦,李靖.非饱和黄土的结构强度与抗剪强度[J].水利学报,2001,(7):79-83
[39]陈开圣.公路工程压实黄土的强度与变形及其微观结构研究[D].西安:长安大学博士学位论文,2006
[40]徐长有.高速公路湿陷性黄土地基处治的研究[D].东北大学硕士学位论文,2002
[41]林崇义.黄土的结构特性[M].中国科学院土木建筑研究所土力学研究室.北京:科学出版社,1961
[42]张炜,张苏民.黄土性质试验中的若干问题[J].工程勘察,1995(3):6-12
[43]范敏.路基黄土压实前后的工程特性试验研究[D].西安:长安大学硕士学位论文,2006
[44]GB/T 50123-1999,土工试验方法标准[S].北京:中国计划出版社,1999
[45]钱家欢,殷宗泽.土工原理与计算(第二版)[M].北京:中国水利水电出版社,1996
[46]刘祖典,党发宁.土的弹塑性理论基础[M].西安:世界图书出版社,2002:53-71
[47]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社,1997:130-141
[48]关文章.湿陷性黄土工程性能新编[M].西安:西安交通大学出版社,1990:147-149
[49]杨位洗.地基与基础[M].北京:中国建筑工业出版社,1998:155-156
[50]陈希哲.土力学地基基础[M].北京:清华大学出版社,2003:77-82
[51]GB 50025-2004.湿陷性黄土地区建筑规范[S].北京:中国建筑出版社,2004
[52]JTJ 024-83.公路桥涵地基与基础设计规范[S].北京:人民交通出版社,1985
[53]罗嘉运.岩土工程与路基[M].北京:中国铁道出版社,2006:182-188
[54]JTJ 033-95.公路路基施工技术规范[S].北京:人民交通出版社,1985
[55]刘吉士、阎洪河.公路路基施工技术[M].北京:人民交通出版社,2003:440-457
[56]工程地质手册编写委员会.工程地质手册(第三版)[M].北京:中国建筑工业出版社,1990:217-268
[2]乔平定,李增均.黄土地区工程地质[M].北京:水利水电出版社,1990:3
[3]Hu,R.L.etc,Mechanical behavior and microstructural variation of loess under dynamic compaction,Engineering Geology,v 59,n 3-4,April,2001,p 203-217
[4]Bowders,John J.Shear behavior of compacted silty loess,Geotechnical Special Publication,n 99,2000,p 235-246
[5]Li,Z.M,Compressibility and collapsibility of compacted unsaturated loessial soils,Proc 1995 1 Int Conf Unsaturated Soils,v 1,1995,p 139
[6]Rabinovich,I.G.etc,Features of deformations of the rammed collapsible soils,Proceedings of the International Conference on Soil Mechanics and Foundation Engineering,v 1,Deformation of Soils and Displacements of Structures X ECSMFE,1991,p 157-158
[7]Minkov,M.etc,Compaction and stabilization of loess in Bulgaria.Proceedings of the International Conference on Soil Mechanics and Foundation Engineering,v 3,1981,p 745-748
[8]Sneddon,Roy V,Stress-strain characterization of two compacted soil,Transportation Research Record,n 548,1975,p 97-103
[9]张宗祜.我国黄土类土显微结构的研究[J].地质学报,1964,44(3):357-364
[10]刘东生.中国黄土的地质环境[J].科学通报,1978,23(1):1-9
[11]高国瑞.黄土显微结构分类与湿陷性[J].中国科学,1980(12):1203-1208
[12]王永焱,林在贯等.中国黄土的结构特征及物理力学性质[M].北京:科学出版社,1990:157-158
[13]雷祥义.中国黄土的孔隙类型与湿陷性[J].中国科学(B辑),1987(12):1309-1316
[14]白晓红,山西潞城黄土的工程特性,岩土工程学报[J],2002,24(4):516-518
[15]谢定义,齐吉琳.土结构性及其定量化参数研究的新途径[J].岩土工程学报,1999,21(6):651-656
[16]齐吉琳,谢定义,石玉成.土结构性的研究方法及现状[J].西北地震学报,2001,23(1):99-102
[17]邵生俊,周飞飞,龙吉勇.原状黄土结构性及其定量化参数研究[J].岩土工程学报,2004,26(4):531-536
[18]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社,1997:115-127
[19]苗天德等.考虑微结构失稳的湿陷性黄土变形机理[J].中国科学(B辑).1990,(1):86-96
[20]Miao T D,Wang Z G..Deformation mechanism of collapsible loess in consideration of the miceostructure instability.Catern Suppl,1991,20:93-105
[21]苗天德等.湿陷性黄土的变形机理与本构关系[J].岩土工程学报.1999,21(4):383-387
[22]杨代泉.非饱和土弹塑性应力应变特性模拟[J].岩土工程学报,1995,17(6):42-49
[23]陈正汉,黄海,卢再华.非饱和土的非线性固结模型与弹塑性固结模型及其应用[J].应用数学与力学,2001,22(1):93-103
[24]景宏君,张斌.黄土路基强度规律.交通运输工程学报[J].2004,4(2):14-18
[25]刘建民.从压实土体的强度特征看黄土的现场压实控制[J].工业建筑.1994,24(10):26-30
[26]杨有海,王丽琴,苏在朝等.重塑黄土的强度特性及其影响因素的研究[J].兰州铁道学院学报.2003,22(3):38-41
[27]胡瑞林,李焯芬,王思敬,等.动荷载作用下黄土的强度特征及结构变化机理研究[J].岩土工程学报.2000,22(2):174-178
[28]胡瑞林,王思敬,李向全,等.模拟强夯下黄土的固结变形特征及其微观分析[J].岩土力学.1999,20(4):12-17
[29]李晓军,张登良.CT技术在土体结构性分析中的应用初探[J].岩土力学.1999,20(2):62-66
[30]李晓军,张登良.路基填土单轴受压细观结构CT监测分析[J].岩土工程学报.2000,22(2):205-209
[31]张玉蕴.黄土微结构研究的回顾与探讨[J].工程建设与设计,2004,(5):10-11
[32]卢肇钧,张惠明,陈建华,等.非饱和土的抗剪强度与膨胀压力[J].岩土工程学报,1992,14(3):1-8
[33]D.G.Fredlund,N.R.Morgenstern,R.A.Widger,The Shear Strength of Unsaturated Soils,Can.Geotech.J.,1978,15(3):313-321
[34]徐永福.非饱和膨胀土的力学特性及其工程应用[D].河海大学博士学位论文,1997
[35]缪林昌,仲晓晨,殷宗泽.膨胀土的强度与含水量的关系[J].岩土力学,1999,20(2):71-75
[36]关文章.湿陷性黄土工程性能新编[M].西安:西安交通大学出版社,1990:17-19
[37]龚晓南.复合地基理论及工程应用[M].北京:中国建筑工业出版社,2002
[38]党进谦,李靖.非饱和黄土的结构强度与抗剪强度[J].水利学报,2001,(7):79-83
[39]陈开圣.公路工程压实黄土的强度与变形及其微观结构研究[D].西安:长安大学博士学位论文,2006
[40]徐长有.高速公路湿陷性黄土地基处治的研究[D].东北大学硕士学位论文,2002
[41]林崇义.黄土的结构特性[M].中国科学院土木建筑研究所土力学研究室.北京:科学出版社,1961
[42]张炜,张苏民.黄土性质试验中的若干问题[J].工程勘察,1995(3):6-12
[43]范敏.路基黄土压实前后的工程特性试验研究[D].西安:长安大学硕士学位论文,2006
[44]GB/T 50123-1999,土工试验方法标准[S].北京:中国计划出版社,1999
[45]钱家欢,殷宗泽.土工原理与计算(第二版)[M].北京:中国水利水电出版社,1996
[46]刘祖典,党发宁.土的弹塑性理论基础[M].西安:世界图书出版社,2002:53-71
[47]刘祖典.黄土力学与工程[M].西安:陕西科学技术出版社,1997:130-141
[48]关文章.湿陷性黄土工程性能新编[M].西安:西安交通大学出版社,1990:147-149
[49]杨位洗.地基与基础[M].北京:中国建筑工业出版社,1998:155-156
[50]陈希哲.土力学地基基础[M].北京:清华大学出版社,2003:77-82
[51]GB 50025-2004.湿陷性黄土地区建筑规范[S].北京:中国建筑出版社,2004
[52]JTJ 024-83.公路桥涵地基与基础设计规范[S].北京:人民交通出版社,1985
[53]罗嘉运.岩土工程与路基[M].北京:中国铁道出版社,2006:182-188
[54]JTJ 033-95.公路路基施工技术规范[S].北京:人民交通出版社,1985
[55]刘吉士、阎洪河.公路路基施工技术[M].北京:人民交通出版社,2003:440-457
[56]工程地质手册编写委员会.工程地质手册(第三版)[M].北京:中国建筑工业出版社,1990:217-268