覆盖型岩溶土洞泡沫混凝土复合地基模型试验研究
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摘要
通过建立室内模型,进行了复合地基变形特性研究试验,研究覆盖型岩溶土洞泡沫混凝土复合地基的变形特性。试验设置两种工况共九组试验,探讨在分级荷载作用下不同桩长形成的复合地基的沉降规律,处理前后的土压力变化规律,以及桩土荷载分担比的变化规律。结果表明,当溶洞无充填物时,利用泡沫混凝土进行充填及作竖向增强体桩,桩体与充填体形成整体,与桩间土共同形成复合地基,地基承载力提升明显。若桩长继续增加,承载力没有提高,桩体工作性状接近端承桩。当溶洞被其它软弱土层充填时,桩长越长,承载力越高,但达到一定长度之后承载力提升有限,桩体工作性状接近摩擦桩。试验结果对泡沫混凝土复合地基处理覆盖型岩溶土洞的应用具有参考价值。
The purpose of this paper was to investigate the deformation characteristics of the covered karst treated by foam concrete composite foundation. The deformation characteristics of the composite foundation were studied by establishing the indoor model. The test set two working conditions and nine tests of composite foundation formed by different pile lengths were done under the hierarchical loads. The settlement regularities,the change rules of soil pressure before and after treatment,and the stress of pile were discussed. The results demonstrated that the foam concrete pile and the foam concrete filling formed a unit without filling in the cave. The composite soil was formed together with the soil between the piles. The bearing capacity of the foundation was obviously improved. With increase in the pile length,the bearing capacity was not improved. The working characteristics of the pile were close to that of the end-bearing pile. When the karst cave was filled by soft soil,the foam concrete pile formed composite foundation with the soil between the piles. The longer the pile length was,the higher the bearing capacity was.However,after reaching a certain length,the bearing capacity reaches its limit. The working characteristics of the pile were close to that of the friction pile. The test results are of great reference value for the application of foamed concrete composite foundation to covered karst.
The purpose of this paper was to investigate the deformation characteristics of the covered karst treated by foam concrete composite foundation. The deformation characteristics of the composite foundation were studied by establishing the indoor model. The test set two working conditions and nine tests of composite foundation formed by different pile lengths were done under the hierarchical loads. The settlement regularities,the change rules of soil pressure before and after treatment,and the stress of pile were discussed. The results demonstrated that the foam concrete pile and the foam concrete filling formed a unit without filling in the cave. The composite soil was formed together with the soil between the piles. The bearing capacity of the foundation was obviously improved. With increase in the pile length,the bearing capacity was not improved. The working characteristics of the pile were close to that of the end-bearing pile. When the karst cave was filled by soft soil,the foam concrete pile formed composite foundation with the soil between the piles. The longer the pile length was,the higher the bearing capacity was.However,after reaching a certain length,the bearing capacity reaches its limit. The working characteristics of the pile were close to that of the friction pile. The test results are of great reference value for the application of foamed concrete composite foundation to covered karst.
引文
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[10]张先华.岩溶地区岩土工程评价及地基基础方案的比选[J].资源环境与工程,2010,24(3):265-267.
[11]苏谦,黄俊杰,白皓,等.铁路站场岩溶地基加固补强技术与效果分析[J].岩土力学,2013,34(3):776-782.
[12]廖文彬.CFG桩复合地基在岩溶地区高层建筑中的应用[J].土工基础,2004,18(6):22-24.
[13]邓磊.覆盖型岩溶地基控制旋喷成桩质量的施工技术[J].路基工程,2012(5):130-132.
[14]潘纪顺,连光明,冷元宝,等.综合物探方法在鹤辉高速公路溶洞勘查中的应用[J].华北水利水电大学学报(自然科学版),2015,36(2):49-53.
[15]周明杰,王娜娜,赵晓艳,等.泡沫混凝土的研究和应用最新进展[J].混凝土,2009(4):104-107.
[16]张福兴.泡沫轻质土在高速铁路软土路基中的应用[D].北京:北京交通大学,2017.
[17]Kearsley E P,Wainwright P J.The effect of porosity on the strength of foamed concrete[J].Cement&Concrete Research,2002,32(2):233-239.
[18]Tikalsky P J,Pospisil J,Macdonald W.A method for assessment of the freeze-thaw resistance of preformed foam cellular concrete[J].Cement&Concrete Research,2004,34(5):889-893.
[2]吴超凡,邱占林,邹丹.福建龙岩新罗区地质灾害形成条件及其机理探讨[J].中国地质灾害与防治学报,2012,23(2):105-110.
[3]周建,张映钱,方亿刚,等.水位变动及降雨入渗联合作用对岩溶地面塌陷的影响分析[J].水利与建筑工程学报,2016,14(1):218-222.
[4]任新红,郭永春,王清梅,等.覆盖型岩溶潜蚀塌陷临界裂隙开度模型试验研究[J].水文地质工程地质,2012,9(5):84-87.
[5]张文,武科,刘国强,等.城市地铁隧道岩溶地质灾害预警与成因分析[J].水利与建筑工程学报,2015,13(2):42-46.
[6]鲍道亮,罗均宇,刘冬梅.覆盖型岩溶区岩溶土洞的分布及地基处理方法[J].龙岩学院学报,2011,29(5):16-20.
[7]毕诗月.压力注浆技术及其在岩溶路基处理中的应用[J].水利与建筑工程学报,2008,6(1):82-83.
[8]黄俊光,方引晴,袁尚红,等.岩溶地区地基基础处理的几个问题分析[J].广州大学学报(自然科学版),2006,5(1):74-77.
[9]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.
[10]张先华.岩溶地区岩土工程评价及地基基础方案的比选[J].资源环境与工程,2010,24(3):265-267.
[11]苏谦,黄俊杰,白皓,等.铁路站场岩溶地基加固补强技术与效果分析[J].岩土力学,2013,34(3):776-782.
[12]廖文彬.CFG桩复合地基在岩溶地区高层建筑中的应用[J].土工基础,2004,18(6):22-24.
[13]邓磊.覆盖型岩溶地基控制旋喷成桩质量的施工技术[J].路基工程,2012(5):130-132.
[14]潘纪顺,连光明,冷元宝,等.综合物探方法在鹤辉高速公路溶洞勘查中的应用[J].华北水利水电大学学报(自然科学版),2015,36(2):49-53.
[15]周明杰,王娜娜,赵晓艳,等.泡沫混凝土的研究和应用最新进展[J].混凝土,2009(4):104-107.
[16]张福兴.泡沫轻质土在高速铁路软土路基中的应用[D].北京:北京交通大学,2017.
[17]Kearsley E P,Wainwright P J.The effect of porosity on the strength of foamed concrete[J].Cement&Concrete Research,2002,32(2):233-239.
[18]Tikalsky P J,Pospisil J,Macdonald W.A method for assessment of the freeze-thaw resistance of preformed foam cellular concrete[J].Cement&Concrete Research,2004,34(5):889-893.