摘要
在沙漠公路建设中,不仅会遇到风积沙施工压实以及防风固沙等技术难题,也会遇到很多特殊路基处理技术问题。其中包括,由于动植物遗体腐化后与风积沙混合形成的特殊路基土处理,以及低洼积水处形成的含淤泥风积沙软弱地基处理等。先期建设的国道210榆林至陕蒙界高速公路(半幅)全线76km路段中遇到了大量特殊地基问题,其中包括20余处海子滩地、淤泥土地基、腐殖土地基及牲畜粪便地基等特殊地基路段；同时也有十几公里地下水位接近地表的路段。后续开工建设的的另半幅沿线88kmn中,4km为河谷阶地沉积区,地层以含水量高的细沙土为主,地基承载力较低；53kmn为湖盆滩地区,地下水埋藏较浅,雨季低洼处常积水形成海子或湿地,地表为冲积或湖积淤泥质亚粘土,地基多具有水平层状结构；18km大部分位于湖盆滩地上,局部有盐碱土,地下水位较高,特殊地质路段分布较广。可见特殊路基处理问题成为该沙漠地区高速公路建设中的突出问题。
本文在调查和收集国内外沙漠公路有关资料的基础上,以榆林至陕蒙界沙漠高速公路为依托,对沙漠公路特殊路基处理技术开展了以下研究：
1.通过室内试验,研究了不同含泥量风积沙的物理特性,对不同含泥量风积沙的工程地质特性进行了评价。通过对不同含泥量风积沙的压实试验,研究了不同含泥量风积沙的压实特性。
2.研究了不同含泥量风积沙力学指标的变化范围,给出了不同含泥量风积沙最大干密度的确定方法；对不同含泥量风积沙的路用性能进行了综合评价,提出了适合作为路基填料的含泥量范围。
3.在陕蒙沙漠公路选取6处试验段,对天然地基和不良地基处理后的承载力进行了载荷试验研究,提出了地基处理技术措施。
4.采用有限元软件对风积沙的天然地基和处理后的地基进行数值分析,从地基承载力和地基变形方面探讨风积沙地基力学特性。结果表明当土体强度参数与实际情况接近时,用有限元分析软件模拟与现场载荷试验具有一致性,两种方法结果接近。采用有限元分析方法对不良地基处理前后进行了数值分析,分析结果表明经过处理后,地基的工程特性明显改善。
5.应用范例推理方法预测风积沙路基最终沉降,在以往的风积沙路基沉降和当前的风积沙路基沉降预测之间建立了合理的推理关系。计算预测结果与实际接近,具有较强适用性。同时为了比较验证,也对风积沙地基采用传递矩阵法进行了应力和位移计算。
6.对陕蒙高速公路特殊地基的各种处理方案采用灰色区间关联决策方法进行了优化分析,通过对每一个影响工程处理方案选择的因素进行分析,从而找到最大关联度的方案。这种方法对多指标系统的评价贴近于实际。
On expressway construction in the desert, there are many technical problems including problems not only on construction compaction, windbreak and sand fixation but also on special roadbed treatment. The technical problems also include the treatment of special soil mixed with animal and plant remains after corruption and aeolian sand and the treatment of aeolian sand weak foundation containing silt at low-lying stagnant water. In the earlier construction of (the half width) of National Expressway210-Yulin-Shaanxi-Inner Mongolia boundary which totally includes76km, we have encountered many special foundation treatment problems. There are marsh wetland, sludge soil foundation, peat soil foundation and animal waste soil foundation including more than20sties. There are also more than10kilometers roadbed foundation where underground water level is close to the surface level. In the subsequent construction of another half width (88km) of National Expressway210, there are4km river valley terrace deposition area, the strata primary consisting of fine sand with high water content, and the bearing capacity is low. There are53km lake basin beach land along the road and the groundwater has relatively shallow burial depth. When rainy season comes, the low-lying sites often gather water and form lake or wet land. The surface soils are alluvial sediments or lacustrine deposit silt clay and most of the foundation soils are have level layered structure. There are18km road mainly locate at lake basin beach land where underground water level is high with saline soil locally. Special geological sections distribute widely. Special roadbed treatment has become the key problems in the desert expressway construction.
After investigating and collecting material of desert expressways at home and abroad for the research, and also building the base on the Yulin-Shaanxi-Inner Mongolia boundary expressway, the main research of the desert expressway special roadbed treatment technologies and findings are as follows:
1、Through the indoor tests, the paper approaches the physical properties of aeolian sand and make the qualitative analysis of the engineering geolgy characters with different sediment percentage. Based on the compacting test of aeolian sand with different sediment percentage, the compacting properties and the compacting mechanism of aeolian sand with different sediment percentages are studied.
2、According to the tests above, the variation range of mechanical properties for aeolian sand with different sediment percentages are revealed. Following these results, the choice of the biggest dry density is obtained. In view of the results obtained, the road-related performance of aeolian sand with different sediment percentages are judged systemically, and the range of sediment percentage fitting for roadbed material is achieved.
3、In Yulin-Shaanxi-Inner Mongolia boundary Expressway, plate loading test was studied at6test sections which were selected to ascertain the bearing capacity of natural foundation and the improved soil foundation. Foundation treatment technique measures were put forward.
4、The natural aeolian foundation and the improved aeolian foundation were studied by numerical analysis of nonlinear finite element method. The mechanical characteristics of aeolian sand foundation was discussed by analysing the bearing capacity and foundation deformation. When the soils strength parameters were close to the reality, the results of numerical analysis of nonlinear finite element method and plate loading test have consistency and the results of two methods approximate to each other. The soft ground was analyzed by finite element method, and the results show when the soft ground was treated, the engineering characteristics was significantly improved.
5、Using case-based reasoning method to predicte aeolian sand roadbed's final sedimentation, we can build a reasonable relationship between the former sedimentation of aeolian sand roadbed and current predicted sedimentation of aeolian sand roadbed. The predicteion of results were close to the reality, and it has wide applicability. In order to verify stress and displacement, we use transfer of matrix method calculated stress and displacement of aeolian sand roadbed.
6、Optimization analysis of different processing for special roadbed treatment of Yulin-Shaanxi-Inner Mongolia boundary Expressway was made by the grey interval incidence degree decision-making. Through analysing every factor which affects the choice of engineering processing scheme, the engineering processing scheme's maximum relating gray was calculated. The evaluation of the grey interval incidence degree decision-making method for multi-index system close to the actual result.
引文
[1]朱震达,吴正,刘恕.中国沙漠概论[M].北京：科学出版社,1980
[2]陈晓光,罗俊宝,张生辉.沙漠地区公路建设成套技术[M].北京：人民交通出版社,2006
[3]王一谋,王建华,祁元,等.中国1:10万沙漠(沙地)分布图.中国科学院寒区旱区环境工程研究所,2000
[4]陕西省统计局,国家统计局陕西调查总队陕西统计年鉴2008[M].北京：中国统计出版社,2008
[5]范红英.陕蒙沙漠公路不良地质路段路基施工技术研究[D].西安：长安大学硕士学位论文,2005
[6]付兵先.不同含泥量风积沙的路用性能研究[D].西安：长安大学硕士学位论文,2006
[7]Terzaghi,K. Theoretical Soil Mechanics [M]. New York, J. Wiley and Sons, Inc.,1943
[8]Terzaghi,K and Peck,R. B. Soil Mechniacs in Engineering Practice [M]. New York, John. Wiley and Sons, Inc.,1967,2nd edation
[9]梁思成.梁思成全集[M].北京：中国建筑工业出版社,2001
[10]李彰明.软土地基加固的理论、设计与施工[M].北京：中国电力出版社,2006
[11]折学森软土地基沉降计算[M].北京：人民交通出版社,2000
[12]王晓谋,袁怀宇.高等级公路软土地基路堤设计与施工技术[M].北京：人民交通出版社,2001
[13]张留俊,王福胜,刘建都.高速公路软土地基处理技术[M].北京：人民交通出版社,2002
[14]支喜兰.黄土地区公路路基地基承载力评价方法研究[D].西安：长安大学博士学位论文,2005
[15]Randa Chahbandar. Settlement of Strip Footings on a Strong Cohesionless Layer Overlying a Weak Deposit[D].PhD Dissertation, Dept. of Civil Engineering, Concordia Unversity, Canada,1993
[16]龚晓南.基础处理手册[M].第三版.北京：中国建筑工业出版社,2008
[17]叶书麟.地基处理工程实例应用手册[M].北京：中国建筑工业出版社,1998
[18]林宗元.岩土工程治理手册[M].北京：中国建筑工业出版社,2005
[19]黄生文.公路工程地基处理手册[M].北京：人民交通出版社,2005
[20]Minna Karstunen., Martino Leoni. Geotechnics of Soft Soils:Focus on Ground Improvement [M]. CRC Press, Inc./Balkema,2008
[21]Mike Moseley., Klaus Kirsch. Ground Improvement [M]. Second Edition, CRC Press, Inc./Balkema,2004
[22]钱家欢,殷宗泽.土工原理与计算.[M].第二版.北京：中国水利水电出版社,1996
[23]Vesic, A. Bearing capacity of deep foundation in sand [R] National Acadamy of Sicences,National Research Council, Highway Research Record,1963, Vol.39,:112-153
[24]Vesic, A. Analysis of Ultimate Loads of Shallow Foundations [J] Journal of the soil mechanics and foundations division,1973, Vol.99, No.1,:45-73
[25]袁凡凡.非均质介质地基破坏机制及极限承载力分析研究[D].天津：天津大学博士学位论文,2002
[26]Meyerhof G G. Influence of rough of base and ground water conditions on the ultimate bearing capacity of foundations [J] Geoteechnique,1955, Vol(5):227-242
[27]Skempton, A,W. The bearing capacity of clay. In:Building Research Congress eds. Selected Papers on Soil mechanics[M]London, Thomas Telford Limited,1984
[28]约瑟夫·E·波勒斯.基础工程分析与设计(第五版)[M].童小东等.北京：中国建筑工业出版社,2004
[29]Hansen,J,B. A revised and extended formula for bearing capacity.[J] Danish Geotechnical Institute Bulletin,1970(28):5-11
[30]Sokolovskii, V,V. Statics of granular media. [M]. J.K. Lusher, A.W.T. Daniel. Oxford, New York:Pergamon Press,1965
[31]张美燕,黄传志.特征线法的极限荷载与地基极限承载[J].中国港湾建设,2005,3：8-12
[32]徐德馨,周玉琴,傅旭东.条形浅基础极限承载力的滑移线解[J].中国农村水利水电,2006,2：86-88
[33]程彩霞,赵均海,魏雪英.统一滑移线与有限元求解路基极限荷载[J].工程力学,2006,V23(83：150-154
[34]陈惠发.土体塑性与极限分析.[M].詹世斌,韩大建,译.北京：人民交通出版社,1995
[35]陈祖煜.土力学经典问题的极限分析上、下限解.[J]岩土工程学报,2002,V21(1):1-11
[36]袁凡凡,栾茂田,闫澍旺,等.倾斜荷载作用下层状非均质地基的极限承载力.[J]岩土力学,2004,Vol25(Supp2):564-567,573
[37]黄传志,苗中海,刘翼熊.土体极限分析的理论与应用[J].中国港湾建设,1999,4：7-13
[38]黄传志,苗中海,曾锡庭.考虑土工合成物抗滑作用的边坡稳定性分析方法[J].中国港湾建设,2000,1:22-25
[39]黄传志,张敬,孙万禾等.非均质土地基承载力的计算方法[J].中国港湾建设,2000,5：38-43
[40]黄传志,张敬,孙万禾.土体极限状态的应力场与极限荷载[J].岩土工程学报,2002,V24(3):389-391
[41]徐干成,李成学,刘平.各项异性和非均质地基上浅基础的极限承载力[J].岩土工程学报,2007,V29(2)：164-168
[42]李亮,杨小礼.圆形浅基础地基承载力极限分析的上限解析解[J].铁道学报,2003,V23(1):94-97.
[43]周中,傅鹤林,李亮.圆形浅基础地基承载力的理论解[J].长沙铁道学院学报,2002,V20(3)：12-16
[44]李伟,熊巨华,杨敏.方形浅基础地基极限承载力的理论解[J].同济大学学报(自然科学版),2002,V32(10)：1325-1327
[45]蒋益平,熊巨华.方形和圆形基础地基极限承载力分析[J].岩土力学,2005,V26(12)：1991-1995
[46]D.Y.Zhu, C.F.Lee, K.T.Law. Determination of bearing capacity of shallow foundations without using superposition approximation[J]. Canadian Geotechnical Journal,2003, V 40(2):450-459
[47]朱大勇.复杂条件下地基承载力系数Ny的上限解[J].力学与实践,1999,V22(4):24-27
[48]中华人民共和国国家标准.建筑地基基础设计规范(GB50007-2002)[S]北京：中国建筑工业出版社,2002
[49]唐贤强,谢瑛,谢树彬等.地基工程原位测试技术[M]北京：中国铁道出版社,1993
[50]中华人民共和国国家标准.湿陷性黄土地区建筑规范(GB50025-2004)[S]北京：中国 建筑工业出版社,2004
[51]中华人民共和国国家标准.岩土工程勘察规范(GB50021-2001)[S]北京：中国建筑工业出版社,2002
[52]顾宝和,周红,朱小林.深层平板载荷试验测定土的变形模量[J].工程勘察,2002,4：1-2,6
[53]吕建兵,刘仰韶,田卿燕.平板载荷试验检测公路桥涵台背回填中粗砂的机理研究[J].公路,2007,2：116-120
[54]铁道部科学研究院等.地基承载力试验研究文集[M]北京：人民铁道出版社,1978
[55]周镜.岩土工程中的几个问题[J].岩土工程学报,1999,V21(1)：2-8
[56]柳飞,杨俊杰,刘红军等.离心模型试验模拟平板载荷试验研究[J].岩土工程学报,2007,V29(6)：880-886
[57]辛建丽.黄土地区公路地基承载力验算方法研究[D].西安：长安大学硕士学位论文,2004
[58]杨旭毅,支喜兰.平板载荷试验用于公路地基承载力评价的合理性研究[J].公路交通科技,2007,4：73-76
[59]邵江.河北省建筑地基承载力确定方法研究[D].天津：河北工业大学硕士学位论文,2005
[60]王成军.黄河三角洲地区地基承载力的确定[D].青岛：中国海洋大学硕士学位论文,2008
[61]黄仙枝.土工带加筋碎石垫层地基的试验应用及理论研究[D].太原：太原理工大学博士学位论文,2005
[62]刘青松,张春雷,王顺才等.淤泥堆场人工硬壳层地基极限承载力室内模拟研究[J].岩土力学,2008,V29(Suup)：667-670
[63]罗琴.新疆石河子地区砂土地基承载力可靠度分析[D].乌鲁木齐：新疆农业大学硕士学位论文,2007
[64]Briaud, J.L., Gibbens, R. Behavior of five large spread footings in sand.[J]Journal of Geotechnical and Geoenvironmental Engineering,1999, V125(9):787-796
[65]Mark Vakher. Load-Deformation Performance of Peat Soil Under Large Concrete Plates.[A]. W. Allen Marr. Geotechnical Measurements:Lab and Field.[C]. Denver: American Society of Civil Engineers,2000:44-55
[66]袁凡凡,闫澍旺,孙万禾.成层土地基基础极限承载力的模型试验研究[J].中国港湾建设,2003,1：14-17,22
[67]邓楚键,唐晓松,郑颖人等.载荷试验有限元数值模拟[J].岩土力学,2007,V28(Suup.)：249-253.
[68]袁凡凡,栾茂田,闫澍旺等.非均质介质破坏机制及承载力的有限元分析[J].岩石力学与工程学报,2005,V24(6)：929-933
[69]马少坤,于劲,刘怡林等.浅基础地基极限承载力的有限元分析[J].武汉理工大学学报,2007,V29(4)：99-102
[70]马少坤,于劲,王蓉等.条形浅基础下无重土地基承载力研究[J].沈阳建筑大学学报(自然科学版),2008,V24(2)：230-233
[71]杨永新,高建红,高建明等.双层地基极限承载力的数值分析[J].包头钢铁学院学报(,2003,V22(2)：280-284
[72]黄齐武,黄茂松,王贵和等.基于下限有限元法的条形浅基础极限承载力分析[J].岩土工程学报,2007,V29(4)：572-579
[73]秦会来,黄茂松.双层地基极限承载力的极限分析上限法[J].岩土工程学报,2008,V30(4)：611-616
[74]黄齐武,贾苍琴.三维地基极限承载力的数值极限分析[J].岩土工程学报,2007,V29(12)：1809-1814
[75]韩冬冬,贾敏才,刘开富等.条形基础极限承载力数值分析[J].岩土力学,2007,V28(10)：2209-2214
[76]S. Frydman., H.J. Burd. Numerical studied of bearing capacity factor Nr[J] Journal of Geotechnical and Geoenvironmental Engineering,1997, V123(1):20-29
[77]P.K. Woodward., D.V. Griffiths. Obersvation on the computation of the bearing capacity factor Nr by finite element [J] Geotechnique,1998, V48(1):137-141
[78]D.V. Griffiths. Computatiom of the bearing capacity factors using finite element [J] Geotechnique,1982, V32(3):195-202
[79]N Manoharan, S.P Dasgupta. Bearing capacity of surface footings by finite elements [J] Computers and Structures,1995, V54(4):563-586
[80]S.W. Sloan, M.F. Randolph. Numerical prediction of collapse loads using finite element methods [J] International Journal for Numerical and analytical methods in geomechanics,1982, V6:47-76
[81]Terzaghi K. Erdbaumechanik and bodenphysikalischer grundlage [M] Lpz. Deuticke, 1925,27-40
[82]Redulic L. Porenziffer and porenwasserdruck in tonen[M] Bauingenieur,1936,77-95
[83]Biot M A. General theory of three dimensional consolidation [J] J. of Applied Physics, 1941,36-42
[84]郝传毅,饶鸿雁等.路基自身压缩的非线性有限元分析[J].中国公路学报,1991,V4(10)：2209-2214
[85]魏汝龙.软粘土的强度与变形[M].北京：人民交通出版社,1987,85-92
[86]谢新宇等.饱和土体一维大变形固结理论研究[J].西安公路交通大学学报,1996,V16(4)：31-36
[87]刘奉银,赵然,谢定义等.黄土高填方路堤沉降分析[J].长安大学学报(自然科学版),2003,V23(6)：58-63
[88]景宏君.振动压实黄土高路堤沉降变形[D].西安：长安大学博士学位论文,2004
[89]朱梅生.软土地基[M].北京：中国铁道出版社,1989,6-37
[90]汤连生,刘增贤.软土路基工后沉降组成分析[J].城市勘测,2002,2:6-8
[91]陈环.土力学和基础[M].天津：天津大学出版社,1980,40-55
[92]高大钊,袁聚云,谢永利.土质学与土力学[M].北京：人民交通出版社,2001,3-13
[93]肖昭然,吴洪涛,杨青.分层总和法计算沉降的改进[J].山东建筑工业学院学报,1994,V 9(2)：22-26
[94]华南理工大学等.地基与墓础(第1版)[M].北京：中国建筑工业出版社,1991:8-120
[95]罗晓辉.粘性土地基沉降计算方法分析[J].武汉城市建设学院学报.1996,V13(3):67-70
[96]赵树德,廖红建.土力学[M].北京：高等教育出版社,2001：1-20
[97]Schiffman R.L., Chen A. T.F. An analysis of consolidation theories[J]. J. of S.M. and F. Division, SCE,1969,Vol.95, No.SM1:50-70
[98]沈珠江.结构性粘土的弹塑性损伤模型[J].岩土工程学报,1993,V15(3):30-38
[99]曾国熙,龚晓南.软土地基固结有限元分析[J].浙江大学学报.1983(1):1-14
[100]周焕云,黄晓明.高速公路软土地基沉降预测方法综述[J]..交通运输工程学报,2002,V2(4)：7-10
[101]胡中雄.土力学和环境土工学[M].上海：同济大学出版社.1997:22-87
[102]冯文凯,刘汉超.修正双曲线法在路基沉降变形初期阶段的应用探讨[J].地质灾害与环境保护,.2001,V12(3):60-63
[]03]宰金泯,梅国雄.成长曲线在地基沉降预测中应用[.J].南京建筑工程学院学报,2000,2：8-13
[104]宋彦辉,聂德新.基础沉降预测的Verhulst模型[J].岩土力学,2003,V24(1)：123-126
[105]石世云.多变量灰色模型MGM(1,n)在变形预测中的应用[J].测绘通报,1998,(1 0):9-12
[106]张仪萍,龚晓南.沉降的灰色预测[J]..工业建筑,1999,V29(4):45-48
[107]韩女才,李亮,付鹤林.应用灰色理论对地基沉降进行不等时距预测[J].探矿工程,2000,2：7-9
[108]曾超,肖峰,唐仲华.应用灰色模型(G M)预测软土路基沉降量[J].安全和环境工程,2002,V9(1)：17-19
[109]焦李成.神经网络系统理论[M].西安：西安电子科技大学出版社,1998:4-16
[110]闻新Matlab神经网络应用设计[M].北京：科学技术出版社,2000:11-50
[111]刘勇健.用人工神经网络预测高速公路的软土地基的最终沉降[J].公路交通科技,2000,V17(6)：15-18
[112]吴正.中国沙漠及其治理[M].北京：科学出版社,2009,546-555.
[113]薛鹏程.沙漠·湿地·水一榆林北部毛乌素沙区湿地生态环境研究[M].先：陕西科学技术出版社,2006,4-7.
[114]杨持.沙漠化控制与治理技术[M].北京：化学工业出版社,2004,101-103
[115]中华人民共和国行业标准.公路土工试验规程(JTG E40-2007)[S]北京：人民交通出版社,2007
[116]陈火红,杨剑,薛小香等.新编Marc有限元实例教程[M]北京：机械工业出版社,2007
[117]秦丰.土工合成材料加筋软基路堤的有限元分析[D].天津：天津大学硕士士学位论文,2001
[118]申爱琴,郑南翔,苏毅等,含沙低液限粉土填筑路基压实机理及施工技术研究.中国公路学报[J],2000
[119]榆林公路管理局,长安大学.毛乌素沙漠高填方路基的压实和稳定性研究,2000
[120]西安公路研究所,榆林公路总段·无砂石料地区公路修建技术研究报告·1995
[121]何莉娟.沙漠地基处理方法探讨·天然气与石油；1998年
[122]邓聚龙.灰理论基础[M].武汉：华中科技大学出版社,2002
[123]刘思峰,党耀国,方志耕.灰色系统理论及其应用[M].北京：科学出版社,2002
[124]唐伟勤,肖新平.灰关联分析在复杂系统多层次评估中的应用[J].武汉理工大学学报(交通科学与工程版),2004,28(2)：288-290,297.
[125]罗党,刘思峰.灰色多指标风险型决策方法研究.系统工程与电子技术[J]2004,Vo1.22(8)：29-32
[126]许树柏.实用决策方法一层次分析法原理[M].天津,天津大学出版社1988
[127]胡召音.灰色理论及其应用研究[J].武汉理工大学学报(交通科学与工程版),2004,27(3)：405-407,411
[128]高景伟,姬怀卿,董秀坤.陕蒙高速公路软基处理方案优选方法[J]公路交通科技,2006,23(12)：41-44