深厚软质岩土石混合料地基桩基负摩阻力现场试验及数值模拟研究
|
摘要
受用地制约,现有大部分电力工程建设都在山区,场地平整后存在深厚的填土,且成份多以土石混填为主,组成极不均匀。位于此类地基中的桩基后期会产生较大负摩阻力,对桩基承载力影响较大。本文对土石混合填方区中的桩基负摩阻力展开了现场试验研究,得出负摩阻力的大小、中性点位置以及随时间的变化规律,并且与抗拔试验进行对比分析,提出了确定负摩阻力合理科学的计算方法。同时通过数值模拟,得出不同压实度,不同桩径及不同填土厚度对桩侧负摩阻力时效演变规律的影响,为更好地进行桩基设计提供基础。
The electric power projects are always constructed in mountain area subjected to land use. The construction site is filled deeply and thickly with the inhomogeneous mixture of rock and soil in the site formation. Negative friction will exist in the piles constructed in this kind of ground and affects the pile capacity greatly. The in-situ pile negative skin friction test is carried out to study the negative friction value, neutral point and the evolvement rule with time. Compared the results with the pile pulling test, a scientific and reasonable method to calculate the negative friction is recommended. Meanwhile the influence of the compactness, pile diameter and the fill thickness on pile negative skin friction with time is studied by numerical simulation. The conclusion could be used for pile design.
The electric power projects are always constructed in mountain area subjected to land use. The construction site is filled deeply and thickly with the inhomogeneous mixture of rock and soil in the site formation. Negative friction will exist in the piles constructed in this kind of ground and affects the pile capacity greatly. The in-situ pile negative skin friction test is carried out to study the negative friction value, neutral point and the evolvement rule with time. Compared the results with the pile pulling test, a scientific and reasonable method to calculate the negative friction is recommended. Meanwhile the influence of the compactness, pile diameter and the fill thickness on pile negative skin friction with time is studied by numerical simulation. The conclusion could be used for pile design.
引文
[1] 周淼,结构性软土固结及桩基负摩阻性状研究[D].杭州:浙江大学, 2005.Zhou Miao. One dimensional consolidation behavior of structured soil and negative skin friction[D]. Hangzhou: Zhejiang University,2005. (in Chinese)
[2] 徐兵,曹国福.部分桩身在回填土中的钻孔灌注桩负摩阻力试验研究[J].岩土工程学报, 2006,28(1):56～58.Xu Bing,Cao Guofu. Study on negative friction of bored piles in backfilling clay[J]. Chinese Journal of Geotechnical Engineering, 2006,28(1):56～58. (in Chinese)
[3] 黄雪峰,陈正汉,哈双等.大厚度自重湿陷性黄土中灌注桩承载性状与负摩阻力的试验研究[J].岩土工程学报,2007,29(3):338～346.Huang Xuefeng,Chen Zhenghan, Ha Shuang et al. Research on bearing behaviors and negative friction force for filling piles in the site of collapsible loess with big thickness[J]. Chinese Journal of Geotechnical Engineering, 2007,29(3):338～346. (in Chinese)
[4] 律文田,冷伍明,王永和. 软土地区桥台桩基负摩阻力试验研究[J]. 岩土工程学报, 2005,27(6):45～55.Lü Wentian, Leng Wuming, Wang Yonghe. In-situ tests on negative friction resistance of abutment piles in soft soil[J]. Chinese Journal of Geotechnical Engineering, 27(6):45～55. (in Chinese)
[5] 夏力农,柳红霞,欧名贤. 垂直受荷桩负摩阻力时间效应的试验研究[J]. 岩石力学与工程学报,2009,28(6):1177～1182.Xia Linong, Liu Hongxia, Ou Mingxian. Experimental research on time effects of negative skin friction behaviors of vertical-loaded piles[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(6):1177～1182. (in Chinese)
[6] 李玲玲,王立忠. 大直径钻孔灌注桩负摩阻力试验研究[J]. 岩石力学与工程学报, 2009,28 (3):583～589. Li Lingling, Wang Lizhong. Experimental research on negative skin friction of large-diameter bored piles[J]. Chinese Journal of Rock Mechanics and Engineering, 2009,28 (3):583～589. (in Chinese)
[7 ] 许建.新近厚填土场地桩基负摩阻力特征及嵌岩桩设计方法研究[D].成都:西南交通大学,2013.Xu Jian. The negative skin friction characteristics and research on design method of rock-socketed piles in deep recent filling soils area[D]. Chengdu: Southwest Jiaotong University,2013. (in Chinese)
[8 ] 张晓健,陈吉琴. 湿陷性黄土地基桩基负摩阻力简化计算[J]. 工程勘察,2009, 37 (7):14～17.Zhang Xiaojian,Chen Jiqin. Simplified calculation of negative friction for pile foundation in collapsible loess[J]. Geotechnical Investigation & Surveying, 2009, 37 (7):14～17. (in Chinese)
[9] 中华人民共和国行业标准. 建筑桩基技术规范(JGJ 94-2008)[S]. 北京:中国建筑工业出版社,2008.The Professional Standards of the People’s Repbulic of China. Technical code for building pile foundations(JGJ 94-2008)[S]. Beijing: China Architecture & Building Press,2008. (in Chinese)Experimental and numerical study on pile negative friction in deep and thick backfill ground consisted of soft rock and soil Zhang Xiaojian et al.(24)
[2] 徐兵,曹国福.部分桩身在回填土中的钻孔灌注桩负摩阻力试验研究[J].岩土工程学报, 2006,28(1):56～58.Xu Bing,Cao Guofu. Study on negative friction of bored piles in backfilling clay[J]. Chinese Journal of Geotechnical Engineering, 2006,28(1):56～58. (in Chinese)
[3] 黄雪峰,陈正汉,哈双等.大厚度自重湿陷性黄土中灌注桩承载性状与负摩阻力的试验研究[J].岩土工程学报,2007,29(3):338～346.Huang Xuefeng,Chen Zhenghan, Ha Shuang et al. Research on bearing behaviors and negative friction force for filling piles in the site of collapsible loess with big thickness[J]. Chinese Journal of Geotechnical Engineering, 2007,29(3):338～346. (in Chinese)
[4] 律文田,冷伍明,王永和. 软土地区桥台桩基负摩阻力试验研究[J]. 岩土工程学报, 2005,27(6):45～55.Lü Wentian, Leng Wuming, Wang Yonghe. In-situ tests on negative friction resistance of abutment piles in soft soil[J]. Chinese Journal of Geotechnical Engineering, 27(6):45～55. (in Chinese)
[5] 夏力农,柳红霞,欧名贤. 垂直受荷桩负摩阻力时间效应的试验研究[J]. 岩石力学与工程学报,2009,28(6):1177～1182.Xia Linong, Liu Hongxia, Ou Mingxian. Experimental research on time effects of negative skin friction behaviors of vertical-loaded piles[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28(6):1177～1182. (in Chinese)
[6] 李玲玲,王立忠. 大直径钻孔灌注桩负摩阻力试验研究[J]. 岩石力学与工程学报, 2009,28 (3):583～589. Li Lingling, Wang Lizhong. Experimental research on negative skin friction of large-diameter bored piles[J]. Chinese Journal of Rock Mechanics and Engineering, 2009,28 (3):583～589. (in Chinese)
[7 ] 许建.新近厚填土场地桩基负摩阻力特征及嵌岩桩设计方法研究[D].成都:西南交通大学,2013.Xu Jian. The negative skin friction characteristics and research on design method of rock-socketed piles in deep recent filling soils area[D]. Chengdu: Southwest Jiaotong University,2013. (in Chinese)
[8 ] 张晓健,陈吉琴. 湿陷性黄土地基桩基负摩阻力简化计算[J]. 工程勘察,2009, 37 (7):14～17.Zhang Xiaojian,Chen Jiqin. Simplified calculation of negative friction for pile foundation in collapsible loess[J]. Geotechnical Investigation & Surveying, 2009, 37 (7):14～17. (in Chinese)
[9] 中华人民共和国行业标准. 建筑桩基技术规范(JGJ 94-2008)[S]. 北京:中国建筑工业出版社,2008.The Professional Standards of the People’s Repbulic of China. Technical code for building pile foundations(JGJ 94-2008)[S]. Beijing: China Architecture & Building Press,2008. (in Chinese)Experimental and numerical study on pile negative friction in deep and thick backfill ground consisted of soft rock and soil Zhang Xiaojian et al.(24)