岩溶地区复合地基承载力的计算
|
摘要
在广东省岩溶地区工程实践的基础上,总结出4个方面岩溶地质特征,分析其对岩溶地区复合地基工作机理及地基承载力的影响,给出了各主要参数的取值原则,提出了考虑岩溶发育程度的岩溶地区复合地基承载力计算方法,并用该方法对某实际工程进行不同桩型复合地基承载力的试算比选。借助岩溶地区现场3组预应力高强混凝土管桩(PHC桩)+高压旋喷桩复合地基大压板静载试验,通过布置土压力盒,测定并分析PHC桩桩顶、高压旋喷桩桩顶和桩间土体应力及其承载力特征值,计算桩土荷载分担比,分析静载试验中桩、土的受力特性。试验结果与设计计算得出的岩溶地区复合地基承载力特征值基本吻合,表明岩溶地区复合地基承载力计算方法安全可靠;在复合地基中,PHC桩桩土应力比为15～48,高压旋喷桩为1. 5～8,PHC桩桩顶应力集中显著; PHC桩承担了70%以上的荷载,高压旋喷桩和桩间土承担荷载总计不超过30%。
On the basis of engineering practice of karst area in Guangdong,four characteristics of karst geology were summarized. The influence on the working mechanism and bearing capacity of composite foundation were analyzed.The principles for determining the main parameters were given. The calculation method for the bearing capacity of composite foundation considering karst development degree was presented. The calculation method was applied to calculate and compare the bearing capacity of different composite foundations treated with different kinds of pile or piles combination. Three static load tests with large pressure plate on PHC pile + high pressure jet grouting pile composite foundation were carried out in karst area. The earth pressure cells were arranged to measure the bearing capacity of PHC,high pressure jet grouting pile and soil between piles. The load sharing ratio of pile-soil was calculated. The mechanics of pile and soil were analyzed. It was shown that the calculated result of bearing capacity of composite foundation in karst area was similar to the test results. The load sharing ratio of pile-soil of PHC pile was between 15 to 48 and the load sharing ratio of high pressure jet grouting pile was between 1. 5 to 8. The stress concentration on the top of PHC was significant. The load shared by PHC pile was over 70%. The load shared by high pressure jet grouting pile and soil was less than 30%.
On the basis of engineering practice of karst area in Guangdong,four characteristics of karst geology were summarized. The influence on the working mechanism and bearing capacity of composite foundation were analyzed.The principles for determining the main parameters were given. The calculation method for the bearing capacity of composite foundation considering karst development degree was presented. The calculation method was applied to calculate and compare the bearing capacity of different composite foundations treated with different kinds of pile or piles combination. Three static load tests with large pressure plate on PHC pile + high pressure jet grouting pile composite foundation were carried out in karst area. The earth pressure cells were arranged to measure the bearing capacity of PHC,high pressure jet grouting pile and soil between piles. The load sharing ratio of pile-soil was calculated. The mechanics of pile and soil were analyzed. It was shown that the calculated result of bearing capacity of composite foundation in karst area was similar to the test results. The load sharing ratio of pile-soil of PHC pile was between 15 to 48 and the load sharing ratio of high pressure jet grouting pile was between 1. 5 to 8. The stress concentration on the top of PHC was significant. The load shared by PHC pile was over 70%. The load shared by high pressure jet grouting pile and soil was less than 30%.
引文
[1]中华人民共和国住房和城乡建设部.建筑地基处理技术规范:JGJ 79—2012[S].北京:中国建筑工业出版社,2013.
[2]中华人民共和国住房和城乡建设部.复合地基技术规范:GB/T50783—2012[S].北京:中国计划出版社,2012.
[3]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,2007.
[4]龚晓南.复合地基发展概况及其在高层建筑中的应用[J].土木工程学报,1999,32(2):3-10.
[5]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.
[6]牛志荣,李宏,穆建春,等.复合地基处理及其工程实例[M].北京:中国建材工业出版社,2000.
[7]广东省住房和城乡建设厅.刚性-亚刚性桩三维高强复合地基技术规程:DBJ/T 15-79—2011[S].北京:中国建筑工业出版社,2011.
[8]中华人民共和国住房和城乡建设部.刚-柔性桩复合地基技术规程:JGJ/T 210—2010[S].北京:中国建筑工业出版社,2010.
[9]广东省住房和城乡建设厅.建筑地基基础设计规范:DBJ/T15-31—2016[S].北京:中国建筑工业出版社,2016.
[10]广东省住房和城乡建设厅.建筑地基处理技术规范:DBJ/T15-38—2005[S].北京:中国建筑工业出版社,2005.
[11]夏至永,唐小娟. CFG桩复合地基在桂林岩溶地区的应用[J].工程勘察,2006(增刊):113-118.
[12]刘明华.岩溶地区刚性桩复合地基桩间土承载力折减系数取值分析[J].湖南工业职业技术学院学报,2014,14(5):15-17.
[13]马永峰,张志豪.岩溶地区CFG桩复合地基现场试验研究[J].人民长江,2015,46(12):63-67.
[14]叶观宝,孟明辉,邢皓枫.基于有限元计算的岩溶区CFG桩复合地基分析[J].煤田地质与勘探,2011,39(3):44-51.
[15]广东省地质物探工程勘察院.广州市荔湾区大坦沙5017地段项目场地工程地质详细勘察报告[R].广州:广东省地质物探工程勘察院,2014.
[16]万志勇,韩建强,高玉斌,等. CM桩复合地基在岩溶地区高层建筑中的应用[J].建筑结构,2012,42(6):118-120.
[17]林奕禧,张伟丽,黄良机,等.水泥土搅拌桩复合地基承载力折减系数α和β的试验研究[J].岩石力学与工程学报,2009,28(增刊2):3815-3819.
[18]中华人民共和国建设部.建筑地基处理技术规范:JGJ 79—2002[S].北京:中国建筑工业出版社,2002.
[19]中华人民共和国建设部.建筑地基处理技术规范:JGJ 79—91(1998年版)[S].北京:中国建筑工业出版社,2000.
[2]中华人民共和国住房和城乡建设部.复合地基技术规范:GB/T50783—2012[S].北京:中国计划出版社,2012.
[3]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,2007.
[4]龚晓南.复合地基发展概况及其在高层建筑中的应用[J].土木工程学报,1999,32(2):3-10.
[5]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.
[6]牛志荣,李宏,穆建春,等.复合地基处理及其工程实例[M].北京:中国建材工业出版社,2000.
[7]广东省住房和城乡建设厅.刚性-亚刚性桩三维高强复合地基技术规程:DBJ/T 15-79—2011[S].北京:中国建筑工业出版社,2011.
[8]中华人民共和国住房和城乡建设部.刚-柔性桩复合地基技术规程:JGJ/T 210—2010[S].北京:中国建筑工业出版社,2010.
[9]广东省住房和城乡建设厅.建筑地基基础设计规范:DBJ/T15-31—2016[S].北京:中国建筑工业出版社,2016.
[10]广东省住房和城乡建设厅.建筑地基处理技术规范:DBJ/T15-38—2005[S].北京:中国建筑工业出版社,2005.
[11]夏至永,唐小娟. CFG桩复合地基在桂林岩溶地区的应用[J].工程勘察,2006(增刊):113-118.
[12]刘明华.岩溶地区刚性桩复合地基桩间土承载力折减系数取值分析[J].湖南工业职业技术学院学报,2014,14(5):15-17.
[13]马永峰,张志豪.岩溶地区CFG桩复合地基现场试验研究[J].人民长江,2015,46(12):63-67.
[14]叶观宝,孟明辉,邢皓枫.基于有限元计算的岩溶区CFG桩复合地基分析[J].煤田地质与勘探,2011,39(3):44-51.
[15]广东省地质物探工程勘察院.广州市荔湾区大坦沙5017地段项目场地工程地质详细勘察报告[R].广州:广东省地质物探工程勘察院,2014.
[16]万志勇,韩建强,高玉斌,等. CM桩复合地基在岩溶地区高层建筑中的应用[J].建筑结构,2012,42(6):118-120.
[17]林奕禧,张伟丽,黄良机,等.水泥土搅拌桩复合地基承载力折减系数α和β的试验研究[J].岩石力学与工程学报,2009,28(增刊2):3815-3819.
[18]中华人民共和国建设部.建筑地基处理技术规范:JGJ 79—2002[S].北京:中国建筑工业出版社,2002.
[19]中华人民共和国建设部.建筑地基处理技术规范:JGJ 79—91(1998年版)[S].北京:中国建筑工业出版社,2000.