路堤软土地基沉降数值分析
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摘要
80年代以来，随着我国公路建设的迅猛发展，在软土地区兴建公路日益增多。由于路堤软土地基沉降预估的复杂性，准确地预估路堤软基的沉降量，特别是预估软基沉降与时间的关系便成为公路设计的重要问题。而用常规方法计算的路堤软基沉降值与实测资料相比存在较大的误差，故本文作者引入BIOT固结理论，对路堤软基沉降作非线性有限元分析。
本文首先根据BIOT固结理论与有限元原理，用FORTRAN语言编制了平面应变条件下考虑地基土体BIOT固结的非线性有限元程序BP。该程序包括了土体单元、加筋体单元、接触面单元和桩体单元。其中土体采用了Duncan—chang双曲线本构模型，可以考虑土的应力-应变的非线性特征。该程序可用于加筋堤、桩体复合地基和砂井地基等多种路堤软基的沉降计算，同时又可计算路堤软基在各个时刻的侧向变形和孔隙压力值，并能模拟各种施工加载情况。本文用一维固结问题考题，用程序BP计算的结果与太沙基理论解析解十分吻合，证明此程序是基本可靠的。
本文应用有限元程序BP计算了一个假设的路堤软基的沉降，与常规路堤软基沉降方法进行比较，得出了BIOT固结有限元法更为真实地反映侧向变形对沉降的影响、更为合理地计算各个时刻的沉降量、便于考虑施工分级加载对沉降的影响等结论。
本文应用有限元程序BP计算了砂井地基、二灰土桩复合地基和加筋堤软基等三个工程实例。从前两个工程实例的计算结果来看，路堤软基沉降的有限元计算值与工程现场实测值比较接近，吻合程度较高，孔隙压力的变化也比较令人满意，说明本文编制的BIOT固结有限元程序BP有较高的可靠性和实际应用价值。根据计算结果分析，得出了路堤软基沉降、侧向变形和孔隙压力随时间及荷载的变化规律。本文第三个实例分别采用了Duncan-chang非线性模型和线弹性模型计算，将其计算结果与实测资料进行比较，结果证明用非线性模型比较符合工程实际。
Since the 1980's, with the rapid development of highway construction, there are more and more roads built on the soft soil. Because of the difficulty in estimating the settlement of soft ground, how to estimate the settlement of soft ground well and truly, especially to estimate the relation between settlement and time is becoming an important problem of highway design. However, compared with the measured results, the results calculated by the ordinary method usually can't meet the demand. So in this thesis, the author introduced the Biot consolidation theory and analyze the settlement of soft ground with the nonlinear Finite Element Method.
On the base of the Biot consolidation theory and the principle of Finite Element Method, the author developed a FEM program BP in FORTRAN language. This program includes soil element, reinforcement element, Goodman element and pile element etc. In the program, Duncan-chang model was applied to earth, which can consider the nonlinear relation between the stress and strain. This program can be used to calculate the settlement of various kinds of soft ground under highway embankment, it can also be used to calculate lateral displacement and pore water pressure. In this thesis, the author used this program to calculate one-dimensional consolidation problem, and the results showed that this program was credible.
The author used FEM program BP to calculate the settlement of soft foundation under a supposed highway embankment. Comparing Finite Element Method with ordinary method, the author concluded that the Biot FEM can reflect the influence of lateral displacement more truly, calculate the settlement at every moment more suitably, and consider the progress of construction more easily.
At last, the author analyzed three engineering cases with FEM program BP. From the results of first two engineering cases, it can be found that the results calculated by BP were very close to the measured results. This proved that the FEM program BP is very credible and practical. On the base of the results, the author concluded the rule of settlement, lateral displacement and pore water pressure along with the load and time. In the third engineering case, the author separately adopted Duncan-chang model and linear elastic model. Compared their results with the measured results, the author found that the Duncan-chang model is more suitable to evaluate the settlement of soft ground.
本文首先根据BIOT固结理论与有限元原理，用FORTRAN语言编制了平面应变条件下考虑地基土体BIOT固结的非线性有限元程序BP。该程序包括了土体单元、加筋体单元、接触面单元和桩体单元。其中土体采用了Duncan—chang双曲线本构模型，可以考虑土的应力-应变的非线性特征。该程序可用于加筋堤、桩体复合地基和砂井地基等多种路堤软基的沉降计算，同时又可计算路堤软基在各个时刻的侧向变形和孔隙压力值，并能模拟各种施工加载情况。本文用一维固结问题考题，用程序BP计算的结果与太沙基理论解析解十分吻合，证明此程序是基本可靠的。
本文应用有限元程序BP计算了一个假设的路堤软基的沉降，与常规路堤软基沉降方法进行比较，得出了BIOT固结有限元法更为真实地反映侧向变形对沉降的影响、更为合理地计算各个时刻的沉降量、便于考虑施工分级加载对沉降的影响等结论。
本文应用有限元程序BP计算了砂井地基、二灰土桩复合地基和加筋堤软基等三个工程实例。从前两个工程实例的计算结果来看，路堤软基沉降的有限元计算值与工程现场实测值比较接近，吻合程度较高，孔隙压力的变化也比较令人满意，说明本文编制的BIOT固结有限元程序BP有较高的可靠性和实际应用价值。根据计算结果分析，得出了路堤软基沉降、侧向变形和孔隙压力随时间及荷载的变化规律。本文第三个实例分别采用了Duncan-chang非线性模型和线弹性模型计算，将其计算结果与实测资料进行比较，结果证明用非线性模型比较符合工程实际。
Since the 1980's, with the rapid development of highway construction, there are more and more roads built on the soft soil. Because of the difficulty in estimating the settlement of soft ground, how to estimate the settlement of soft ground well and truly, especially to estimate the relation between settlement and time is becoming an important problem of highway design. However, compared with the measured results, the results calculated by the ordinary method usually can't meet the demand. So in this thesis, the author introduced the Biot consolidation theory and analyze the settlement of soft ground with the nonlinear Finite Element Method.
On the base of the Biot consolidation theory and the principle of Finite Element Method, the author developed a FEM program BP in FORTRAN language. This program includes soil element, reinforcement element, Goodman element and pile element etc. In the program, Duncan-chang model was applied to earth, which can consider the nonlinear relation between the stress and strain. This program can be used to calculate the settlement of various kinds of soft ground under highway embankment, it can also be used to calculate lateral displacement and pore water pressure. In this thesis, the author used this program to calculate one-dimensional consolidation problem, and the results showed that this program was credible.
The author used FEM program BP to calculate the settlement of soft foundation under a supposed highway embankment. Comparing Finite Element Method with ordinary method, the author concluded that the Biot FEM can reflect the influence of lateral displacement more truly, calculate the settlement at every moment more suitably, and consider the progress of construction more easily.
At last, the author analyzed three engineering cases with FEM program BP. From the results of first two engineering cases, it can be found that the results calculated by BP were very close to the measured results. This proved that the FEM program BP is very credible and practical. On the base of the results, the author concluded the rule of settlement, lateral displacement and pore water pressure along with the load and time. In the third engineering case, the author separately adopted Duncan-chang model and linear elastic model. Compared their results with the measured results, the author found that the Duncan-chang model is more suitable to evaluate the settlement of soft ground.
引文
[1]E.W.Brand & R.P.Brenner.Soft clay engineering.Elserier Sclentific Publishing Compomy,Amsterdam,1981.1-8．
[2]折学森．软土地基沉降计算．北京：人民交通出版社，1997．1－2．
[3]赵维灿，施健勇．软土固结与流变．南京：河海大学出版社，1996．1－3．
[4]朱梅生．软土地基．北京：中国铁道出版社，1989．1－10．
[5]吴邦颍，张师德，陈绪禄，等．软土地基处理．北京：中国铁道出版社，1995．2－11．
[6]叶书麟．地基处理．中国建筑工业出版社，1988．5－9．
[7]叶书麟，韩杰，叶观宝，等．地基处理与托换技术．北京：中国工业出版社，1994．7－12．
[8]刘景政，杨索春，钟冬波，等．地基处理与实例分析．北京：中国建筑工业出版社，1998．1-15．
[9]中华人民共和国交通部．JTJ 017—96．中华人民共和国行业标准—公路软土地基路堤设计与施工技术规范．人民交通出版社，1996－12－11．
[10]陈仲颐，周景星，王洪瑾，等．土力学．北京：清华大学出版社，1994．136－140．
[11]龚晓南．高等土力学．杭州：浙江大学出版社，1996．127－128．
[12]曾国熙，龚晓南．软土地基固结有限元法分析．浙江大学学报，1983，第17卷第1期：65－75．
[13]沈珠江，易进栋．海滩软土路基的固结变形分析．岩土工程学报，1987，第9卷第6期：39-45．
[14]殷宗泽，朱泓，吴钰，等．沪宁高速公路地基沉降有限元计算分析．水利水电科技进展，1998，第18卷第2期：22-26
[15]陈景杨，徐泽中，吴钰，等．沪宁高速公路江苏段固结沉降规律分析研究．南京：河海大学，1998．
[16]华东水利学院土力学教研室．土工原理与计算．北京：中国水利出版社，1979．61-65．
[17]钱家欢，殷宗泽．土工数值分析．北京：中国铁道出版社，1991．4-23．
[18]陈慧远．土石坝有限元分析．南京：河海大学出版社，1988．1-68．
[19]洪昌华．堤坝下软基土工织物加筋效果的非线性分析：[硕士学位论文]．福州：福州大学土建学院，1997．
[20]魏瑛莺．复杂土坡稳定问题的非线性有限元分析：[硕士学位论文]．福州：福州大学土建学院，2002．
[21]殷有泉．固体力学非线性有限元引论．北京：北京大学出版社、消华大学出版社，1987．1-22．
[22]潘秋元，朱向荣，谢康和，等．关于砂井地基超载预压的若干问题．岩土工程学报，1991，第13卷第2期：1-11．
[23]朱百里，沈珠江等．计算土力学．上海科学技术出版社，1990．111-113．
[24]赵维炳，陈永辉，龚友平，等．平面应变有限元分析中砂井的处理方法．水利学报，1998，6：53-57．
[25]C.C HIRD, I.C. PYRAH and D. RUSSELL.Finite element modeling of vertical drains beneath embankments on soft ground.Geotechnique,1992,42,No3:499-511.
[26]杨涛，殷宗泽等．软土路基二灰桩加固机理有限元分析．公路，1997，3：19－25．
[27]龚晓南．土工计算机分析．北京：中国建筑工业出版社，2000．32－89．
[28]陈建锋，石振明，陈竹昌，等．砂井地基平面问题转换及其应用．岩土工程技术，2001，1：23－26．
[29]徐洋，谢康和，卢廷浩，等．二灰土桩复合地基三维固结有限元分析．岩土工程学报，2002，第24卷地2期：254－256．
[30]杨涛．复合地基沉降计算理论、位移反分析模型和二灰土桩软基加固试验研究[D]．南京：河海大学，1997．66－91．
[31]杨晓军．土工合成材料加筋地基的机理：[博士学位论文]．杭州：浙江大学土木建筑工程系，1999．
[2]折学森．软土地基沉降计算．北京：人民交通出版社，1997．1－2．
[3]赵维灿，施健勇．软土固结与流变．南京：河海大学出版社，1996．1－3．
[4]朱梅生．软土地基．北京：中国铁道出版社，1989．1－10．
[5]吴邦颍，张师德，陈绪禄，等．软土地基处理．北京：中国铁道出版社，1995．2－11．
[6]叶书麟．地基处理．中国建筑工业出版社，1988．5－9．
[7]叶书麟，韩杰，叶观宝，等．地基处理与托换技术．北京：中国工业出版社，1994．7－12．
[8]刘景政，杨索春，钟冬波，等．地基处理与实例分析．北京：中国建筑工业出版社，1998．1-15．
[9]中华人民共和国交通部．JTJ 017—96．中华人民共和国行业标准—公路软土地基路堤设计与施工技术规范．人民交通出版社，1996－12－11．
[10]陈仲颐，周景星，王洪瑾，等．土力学．北京：清华大学出版社，1994．136－140．
[11]龚晓南．高等土力学．杭州：浙江大学出版社，1996．127－128．
[12]曾国熙，龚晓南．软土地基固结有限元法分析．浙江大学学报，1983，第17卷第1期：65－75．
[13]沈珠江，易进栋．海滩软土路基的固结变形分析．岩土工程学报，1987，第9卷第6期：39-45．
[14]殷宗泽，朱泓，吴钰，等．沪宁高速公路地基沉降有限元计算分析．水利水电科技进展，1998，第18卷第2期：22-26
[15]陈景杨，徐泽中，吴钰，等．沪宁高速公路江苏段固结沉降规律分析研究．南京：河海大学，1998．
[16]华东水利学院土力学教研室．土工原理与计算．北京：中国水利出版社，1979．61-65．
[17]钱家欢，殷宗泽．土工数值分析．北京：中国铁道出版社，1991．4-23．
[18]陈慧远．土石坝有限元分析．南京：河海大学出版社，1988．1-68．
[19]洪昌华．堤坝下软基土工织物加筋效果的非线性分析：[硕士学位论文]．福州：福州大学土建学院，1997．
[20]魏瑛莺．复杂土坡稳定问题的非线性有限元分析：[硕士学位论文]．福州：福州大学土建学院，2002．
[21]殷有泉．固体力学非线性有限元引论．北京：北京大学出版社、消华大学出版社，1987．1-22．
[22]潘秋元，朱向荣，谢康和，等．关于砂井地基超载预压的若干问题．岩土工程学报，1991，第13卷第2期：1-11．
[23]朱百里，沈珠江等．计算土力学．上海科学技术出版社，1990．111-113．
[24]赵维炳，陈永辉，龚友平，等．平面应变有限元分析中砂井的处理方法．水利学报，1998，6：53-57．
[25]C.C HIRD, I.C. PYRAH and D. RUSSELL.Finite element modeling of vertical drains beneath embankments on soft ground.Geotechnique,1992,42,No3:499-511.
[26]杨涛，殷宗泽等．软土路基二灰桩加固机理有限元分析．公路，1997，3：19－25．
[27]龚晓南．土工计算机分析．北京：中国建筑工业出版社，2000．32－89．
[28]陈建锋，石振明，陈竹昌，等．砂井地基平面问题转换及其应用．岩土工程技术，2001，1：23－26．
[29]徐洋，谢康和，卢廷浩，等．二灰土桩复合地基三维固结有限元分析．岩土工程学报，2002，第24卷地2期：254－256．
[30]杨涛．复合地基沉降计算理论、位移反分析模型和二灰土桩软基加固试验研究[D]．南京：河海大学，1997．66－91．
[31]杨晓军．土工合成材料加筋地基的机理：[博士学位论文]．杭州：浙江大学土木建筑工程系，1999．