路基刚性桩复合地基的力学性状分析
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摘要
复合地基目前在我国得到了广泛应用，特别是近期刚性桩复合地基在地基处理中应用较多，但对其的研究还较少，本文就依托一个用复合地基处理路基的工程，研究路基中的刚性桩复合地基的性状。
首先，进行了现场试验研究，对比了柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基的力学性状。发现正常荷载下，两种复合地基路基的受力性状不一样，用建筑垃圾填土桩距较大的素混凝土桩复合地基，浅层应力向桩体集中，并通过桩向深层扩散，桩间土与桩有较大的相对位移，桩顶和桩端的刺入较为明显。而对于用粉质粘土填土桩距较小的柔性搅拌桩，桩间土和桩的相对位移很小，桩群和桩间土形成了一个加固整体，应力在桩顶和桩端较集中，大部分的荷载传到桩端土和下卧层中，起到了很好的扩散荷载的作用。
接着，结合了现场试验进行建模，对本次现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析，得出了其压缩模量值，并用反演得出的参数进行有限元模拟，可得出刚性桩复合地基处理路基中地基土的附加应力分布，复合地基压缩沉降变化，桩体受力，超孔隙水压随时间变化等，和实测情况进行分析比较。
最后，推导出了带垫层的刚性桩复合地基桩土应力比的计算公式，这个公式将垫层分为弹性体和理想弹塑性体两种情况分别进行推导，考虑刚性桩刺入垫层和下卧层的情况，并对公式进行了分析，得出了在刚性桩复合地基中桩土应力比随着垫层模量和桩模量的增大而增大，但都有一极限值，随桩间土模量的增大而减小，也有一极限值。并推导了刚性桩桩顶刺入垫层深度的计算公式。
本文的创新之处在于比较了不同填土材料的柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基处理路基的性状。对现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析。导出了带垫层的刚性桩复合地基桩土应力比的计算公式和刚性桩桩顶刺入垫层深度的计算公式，并对影响公式的多个参数进行了分析。
The Mechanics Property of Rigid Pile Composite Foundation in Roadbed
In these days, composite foundations have been extensively used. Especially the rigid pile composite foundation is paid attention to in Practice engineering. But less research work has been done, this paper works on it.
The first, site experiment is carried out. the paper analyze in-situ testing data of subgrade which is made up of plain concrete pile composite foundation and agitation pile composite foundation including pore pressure, layer settlement of soils between piles, earth pressure, lateral deformations. It is found mat many factors under working load are different between agitation pile composite foundation and plain concrete pile composite foundation, and analyze the reasons, describe the factors of two composite foundations under working load.
The second, the module of the ground consisted of construction garbage is inverse analyzed with finite element analysis. Then some mechanics rule of rigid pile(plain concrete pile) composite foundation is educed. The rule of settlement and pore stress is educed too. Then it is compared with the case which is found in site.
Finally, the paper studies the computing method of pile to soil stress ratio of rigid pile composite foundation with cuhion, and these conditions are thought that the top of pile pierce into cushion and the bottom of pile pierce into underlayer.lt is assumed that the cushion is ideal elastic mass and ideal elastic-plastic mass, then the formula is developed and all parameters 'effects to stress ratio of pile to soil are discussed.
首先，进行了现场试验研究，对比了柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基的力学性状。发现正常荷载下，两种复合地基路基的受力性状不一样，用建筑垃圾填土桩距较大的素混凝土桩复合地基，浅层应力向桩体集中，并通过桩向深层扩散，桩间土与桩有较大的相对位移，桩顶和桩端的刺入较为明显。而对于用粉质粘土填土桩距较小的柔性搅拌桩，桩间土和桩的相对位移很小，桩群和桩间土形成了一个加固整体，应力在桩顶和桩端较集中，大部分的荷载传到桩端土和下卧层中，起到了很好的扩散荷载的作用。
接着，结合了现场试验进行建模，对本次现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析，得出了其压缩模量值，并用反演得出的参数进行有限元模拟，可得出刚性桩复合地基处理路基中地基土的附加应力分布，复合地基压缩沉降变化，桩体受力，超孔隙水压随时间变化等，和实测情况进行分析比较。
最后，推导出了带垫层的刚性桩复合地基桩土应力比的计算公式，这个公式将垫层分为弹性体和理想弹塑性体两种情况分别进行推导，考虑刚性桩刺入垫层和下卧层的情况，并对公式进行了分析，得出了在刚性桩复合地基中桩土应力比随着垫层模量和桩模量的增大而增大，但都有一极限值，随桩间土模量的增大而减小，也有一极限值。并推导了刚性桩桩顶刺入垫层深度的计算公式。
本文的创新之处在于比较了不同填土材料的柔性桩(搅拌桩)和刚性桩(素混凝土桩)复合地基处理路基的性状。对现场试验的建筑垃圾杂填土压缩模量进行了参数反演分析。导出了带垫层的刚性桩复合地基桩土应力比的计算公式和刚性桩桩顶刺入垫层深度的计算公式，并对影响公式的多个参数进行了分析。
The Mechanics Property of Rigid Pile Composite Foundation in Roadbed
In these days, composite foundations have been extensively used. Especially the rigid pile composite foundation is paid attention to in Practice engineering. But less research work has been done, this paper works on it.
The first, site experiment is carried out. the paper analyze in-situ testing data of subgrade which is made up of plain concrete pile composite foundation and agitation pile composite foundation including pore pressure, layer settlement of soils between piles, earth pressure, lateral deformations. It is found mat many factors under working load are different between agitation pile composite foundation and plain concrete pile composite foundation, and analyze the reasons, describe the factors of two composite foundations under working load.
The second, the module of the ground consisted of construction garbage is inverse analyzed with finite element analysis. Then some mechanics rule of rigid pile(plain concrete pile) composite foundation is educed. The rule of settlement and pore stress is educed too. Then it is compared with the case which is found in site.
Finally, the paper studies the computing method of pile to soil stress ratio of rigid pile composite foundation with cuhion, and these conditions are thought that the top of pile pierce into cushion and the bottom of pile pierce into underlayer.lt is assumed that the cushion is ideal elastic mass and ideal elastic-plastic mass, then the formula is developed and all parameters 'effects to stress ratio of pile to soil are discussed.
引文
[1]龚晓南．复合地基理论及工程应用．中国建筑工业出版社，2002，4—5
[2]Terzaghi, K & Peck, R.B. soil mechanics in engineering practice. John Wiley & Sons, New York, N,Y. 1948
[3]Meyerhof, G. Compaction of sands and bearing capacity of piles. J. GE, AECE, 1960, vol, 1O2, no.l, 189-207
[4]Skempton, A .W. Discussion: pile and pile foundations settlement of pile foundations. 1953, Proc. 3rd ICSMFE Zurich ,172-174
[5]Coyle, H.K.&Reese, L.C. load transfer for axially loaded piles in clay. J. SMFD, ASCE, 1996, VOL. 89, NO. 2,1-25
[6]Coyle, H.K.& Sulaiman, I.H. skin friction for steel piles in sand. J. SMF, ASCE, 1967, VOL. 93. NO. 6 261-278
[7]Focht J A & Koch K J Rational analysis of the lateral perfo- rmance of offshore piles groups, proc. 5th offshore tech. conf. Houston. 1973, vol. 2, 701-708
[8]O' Neill, M.W, Ghazzly O I & Ha H B Analysis of three-dimensional pile groups with nonlinear soil response and pile-soil-pile interaction. proc. 9th offshore tech .conf. Houston, 1977, vol. 2,245-256.
[9]Poulos, H.G. Analysis of the settlement of pile groups. Geotechnique. 1968, vol18, No. 3,449-471
[10]Geddes, J.D. Stress in foundation soils due to vertical sub- surface load. Geotechnique. 1966, vol16,231-239
[11]Cheung, Y.K, Tham, L.G.&Guo, D.J. Analysis of pile group by infi- nite layer method. Geotechnique. 1988, vol38, no3,415-431
[12]Chow, Y.K. Analysis of vertically loaded pile groups. Int. J. Numer. Analyt. Meth. Geomech. 1986, Vol. 10. No.1, 59-72
[13]Cook, R.W. The settlement of friction pile foundation .proc. conf. on Tall Building. Kuala Lumpur, 1987
[14]Cooke, R.W.,Price, G.&rarr, k. Tacked pile in london clay:a study of load transfer and settlement under working condition. Geotechnique, 1979, vol 30, no. 2. 97-136
[15]Clemente, J. L. &Polo, J. M. Micro-computer analysis of pile group settlement using independent point and shaft loads. Computer&structures. 1988, vol29, no2.241-255
[16]王启铜．柔性桩的沉降[位移]特性及荷载传递规律，浙江大学博士学位论文．1991
[17]段继伟．柔性桩复合地基的数值分析，浙江大学博士学位论文，1993
[18]池跃君，宋二样，陈肇元．刚性桩复台地基在不同荷载下的桩土分担特性，天津大学学报，2003，vol 36，no3．
[19]张雁，黄强．半刚性桩复合地基性状分析，岩土工程学报，1993，vol15，no2，pp86—93
[20]池跃君，沈伟，宋二祥．垫层破坏模式的探讨及其与桩土应力比的关系，工业建筑，2001，vol31，noll pp9—11．
[21]龚晓南．复合地基发展概况及其在高层建筑中的应用，土木工程学报，1988，vol32，no6，pp3—10．
[22]周健，复合地基加固区沉降计算的一种新方法，浙江大学学报[工学版]，2000，vol34，nol，pp83—87．
[23]宋二祥，沈伟．刚性桩复台地基—筏板基础体系内力、沉陷计算方法，岩土工，程学报，2003，vol25，no3，pp268—272．
[24]傅景辉，宋二祥．刚性桩复合地基工作特性分析，岩土力学，2000，vol21，no4，pp335—339．
[25]吴金维．刚性桩复合地基在高层建筑中的应用，建筑结构，1999，7，pp33—36
[26]陶茂之．高层建筑刚性桩复合地基的设计与研究，1998，5，pp38—42．
[27]沈伟，池跃君，宋二样．考虑桩、土、垫层协同作用的刚性桩复合地基沉降计算方法，工程力学，2003，vol20，no2，36—42．
[28]郑俊杰，彭小荣．桩土共同作用设计理论研究，岩土力学，vol24，no5，pp242
—245
[29]李宁，韩煊．褥垫层对复合地基承载机理的影响，土木工程学报，2001，vol34，no2，pp68—83．
[30]邢仲星，陈晓平．复合地基力学特性研究及有限元分析．土工基础，2000，vol14，no 2，pp1—4．
[31]Harry&Poulos. Piled rafts swelling or consolidate soils. Jnl Geotechnical, 1986, Div, ASCE, 374-380.
[32]R.W. cooke. Axially loaded piles and pile groups embedded in a crossanisotropic soil. Geotechnical, Div, ASCE, 1977,Vol 119 ,230-242.
[33]H.G. Poulos. Piled raft foundation:design and applications. Geotechnique, 2001, vol51, no2,95-113.
[34]C.F. Leung. Phd. Observation of an instrumented pile-raft foundation in weak rock. Proc, mst, civ, engrs, partl, 1986, vol 84.
[35]R.W. Cooke. some observation of the foundation loading and settlement of a muiti-storey building on a piled raft foundation in London clay. Proc. Instn, civ. Engrs. partl. 1981, 70-89.
[36]Juan, M. pestana, Christopher E. Hunt. soil deformation and excess pore pressure field around a closed-ended pile .J. Geotech ASCE, 2002, Vol 128, nol , 1-12.
[37]池跃君，宋二祥．刚性桩复合地基承载及变形特性试验研究．中国矿业大学学报，2002，vol31，no3，pp237—241
[38]张聚山．刚性桩复合地基及工程实例．建筑结构，1997，5，pp40—44
[39]池跃君，宋二祥．刚性桩复合地基应力场分布的试验研究．岩土力学，2003，vol24，no3，339—343
[40]俞大刚．杭州铁路水电段综合楼采用复合地基．铁道建筑，2001，6，10—12
[41]徐嵘，李春蕾．某工程刚性桩复合地基的设计与试验研究，2001，vol29，增刊，192—196．
[42]胡向奎，秦峰．楔形刚性桩复合地基在工程中的应用，2001，12，47-50．
[43]陈强，章宇强．粉喷桩加固软基的应力特性分析．公路，2000[10]，120—123．
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[2]Terzaghi, K & Peck, R.B. soil mechanics in engineering practice. John Wiley & Sons, New York, N,Y. 1948
[3]Meyerhof, G. Compaction of sands and bearing capacity of piles. J. GE, AECE, 1960, vol, 1O2, no.l, 189-207
[4]Skempton, A .W. Discussion: pile and pile foundations settlement of pile foundations. 1953, Proc. 3rd ICSMFE Zurich ,172-174
[5]Coyle, H.K.&Reese, L.C. load transfer for axially loaded piles in clay. J. SMFD, ASCE, 1996, VOL. 89, NO. 2,1-25
[6]Coyle, H.K.& Sulaiman, I.H. skin friction for steel piles in sand. J. SMF, ASCE, 1967, VOL. 93. NO. 6 261-278
[7]Focht J A & Koch K J Rational analysis of the lateral perfo- rmance of offshore piles groups, proc. 5th offshore tech. conf. Houston. 1973, vol. 2, 701-708
[8]O' Neill, M.W, Ghazzly O I & Ha H B Analysis of three-dimensional pile groups with nonlinear soil response and pile-soil-pile interaction. proc. 9th offshore tech .conf. Houston, 1977, vol. 2,245-256.
[9]Poulos, H.G. Analysis of the settlement of pile groups. Geotechnique. 1968, vol18, No. 3,449-471
[10]Geddes, J.D. Stress in foundation soils due to vertical sub- surface load. Geotechnique. 1966, vol16,231-239
[11]Cheung, Y.K, Tham, L.G.&Guo, D.J. Analysis of pile group by infi- nite layer method. Geotechnique. 1988, vol38, no3,415-431
[12]Chow, Y.K. Analysis of vertically loaded pile groups. Int. J. Numer. Analyt. Meth. Geomech. 1986, Vol. 10. No.1, 59-72
[13]Cook, R.W. The settlement of friction pile foundation .proc. conf. on Tall Building. Kuala Lumpur, 1987
[14]Cooke, R.W.,Price, G.&rarr, k. Tacked pile in london clay:a study of load transfer and settlement under working condition. Geotechnique, 1979, vol 30, no. 2. 97-136
[15]Clemente, J. L. &Polo, J. M. Micro-computer analysis of pile group settlement using independent point and shaft loads. Computer&structures. 1988, vol29, no2.241-255
[16]王启铜．柔性桩的沉降[位移]特性及荷载传递规律，浙江大学博士学位论文．1991
[17]段继伟．柔性桩复合地基的数值分析，浙江大学博士学位论文，1993
[18]池跃君，宋二样，陈肇元．刚性桩复台地基在不同荷载下的桩土分担特性，天津大学学报，2003，vol 36，no3．
[19]张雁，黄强．半刚性桩复合地基性状分析，岩土工程学报，1993，vol15，no2，pp86—93
[20]池跃君，沈伟，宋二祥．垫层破坏模式的探讨及其与桩土应力比的关系，工业建筑，2001，vol31，noll pp9—11．
[21]龚晓南．复合地基发展概况及其在高层建筑中的应用，土木工程学报，1988，vol32，no6，pp3—10．
[22]周健，复合地基加固区沉降计算的一种新方法，浙江大学学报[工学版]，2000，vol34，nol，pp83—87．
[23]宋二祥，沈伟．刚性桩复台地基—筏板基础体系内力、沉陷计算方法，岩土工，程学报，2003，vol25，no3，pp268—272．
[24]傅景辉，宋二祥．刚性桩复合地基工作特性分析，岩土力学，2000，vol21，no4，pp335—339．
[25]吴金维．刚性桩复合地基在高层建筑中的应用，建筑结构，1999，7，pp33—36
[26]陶茂之．高层建筑刚性桩复合地基的设计与研究，1998，5，pp38—42．
[27]沈伟，池跃君，宋二样．考虑桩、土、垫层协同作用的刚性桩复合地基沉降计算方法，工程力学，2003，vol20，no2，36—42．
[28]郑俊杰，彭小荣．桩土共同作用设计理论研究，岩土力学，vol24，no5，pp242
—245
[29]李宁，韩煊．褥垫层对复合地基承载机理的影响，土木工程学报，2001，vol34，no2，pp68—83．
[30]邢仲星，陈晓平．复合地基力学特性研究及有限元分析．土工基础，2000，vol14，no 2，pp1—4．
[31]Harry&Poulos. Piled rafts swelling or consolidate soils. Jnl Geotechnical, 1986, Div, ASCE, 374-380.
[32]R.W. cooke. Axially loaded piles and pile groups embedded in a crossanisotropic soil. Geotechnical, Div, ASCE, 1977,Vol 119 ,230-242.
[33]H.G. Poulos. Piled raft foundation:design and applications. Geotechnique, 2001, vol51, no2,95-113.
[34]C.F. Leung. Phd. Observation of an instrumented pile-raft foundation in weak rock. Proc, mst, civ, engrs, partl, 1986, vol 84.
[35]R.W. Cooke. some observation of the foundation loading and settlement of a muiti-storey building on a piled raft foundation in London clay. Proc. Instn, civ. Engrs. partl. 1981, 70-89.
[36]Juan, M. pestana, Christopher E. Hunt. soil deformation and excess pore pressure field around a closed-ended pile .J. Geotech ASCE, 2002, Vol 128, nol , 1-12.
[37]池跃君，宋二祥．刚性桩复合地基承载及变形特性试验研究．中国矿业大学学报，2002，vol31，no3，pp237—241
[38]张聚山．刚性桩复合地基及工程实例．建筑结构，1997，5，pp40—44
[39]池跃君，宋二祥．刚性桩复合地基应力场分布的试验研究．岩土力学，2003，vol24，no3，339—343
[40]俞大刚．杭州铁路水电段综合楼采用复合地基．铁道建筑，2001，6，10—12
[41]徐嵘，李春蕾．某工程刚性桩复合地基的设计与试验研究，2001，vol29，增刊，192—196．
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