浸水型病害引起黄土地基沉降的离心模型试验及修正双曲线估算法
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摘要
采用离心模型试验研究不同基底压力下,地基浸水病害对黄土地基变形的影响规律.结果表明,浸水时,黄土地基的最终沉降量随着基底压力的增大而增大,基础外的点的沉降量随着位置远离基础中心而逐渐减小.地基的最终沉降量和基底压力之间呈线性关系.根据离心试验结果提出了基础中心和基础外点的修正双曲线估算参数.双曲线估算法的2个参数某级压力下的地基最终沉降量和该级压力下的经验参数都随着基底压力的增大而增大,但是基底压力增大引起的某级压力下的地基最终沉降量的增加幅度明显大于该级压力下的经验参数的变化幅度.沉降的实测值和双曲线估算值之间的相关系数为0.96～0.99,表明双曲线估算法的可靠性和高精度.
Centrifugal model test is an important method to study the collapsible deformation characteristics of loess foundation. It was used to study the effect of water immersion on loess foundation deformation under different base pressures and the test results showed that the final settlement of loess foundation increases with the increasing of base pressure, while the settlement of points outside the foundation decreased with the location away from the center. There was a linear relationship between the final settlement of the foundation and the pressure. The correction hyperbolic estimation parameters of the base center and the outside points of the foundation were proposed according to the centrifugal test results. The two parameters of the hyperbolic estimation method, the final settlement of the foundation under a certain base pressure and the corresponding experience parameters increased with the increase of the base pressure, but the increasing amplitude of the final settlement of the foundation caused by the increase of the base pressure was significantly greater than that of the corresponding experience parameter. The correla-tion coefficient between the measured value and hyperbolic estimation value was between 0.96 and 0.99,indicating a reliability and high precision of the hyperbolic estimation method.
Centrifugal model test is an important method to study the collapsible deformation characteristics of loess foundation. It was used to study the effect of water immersion on loess foundation deformation under different base pressures and the test results showed that the final settlement of loess foundation increases with the increasing of base pressure, while the settlement of points outside the foundation decreased with the location away from the center. There was a linear relationship between the final settlement of the foundation and the pressure. The correction hyperbolic estimation parameters of the base center and the outside points of the foundation were proposed according to the centrifugal test results. The two parameters of the hyperbolic estimation method, the final settlement of the foundation under a certain base pressure and the corresponding experience parameters increased with the increase of the base pressure, but the increasing amplitude of the final settlement of the foundation caused by the increase of the base pressure was significantly greater than that of the corresponding experience parameter. The correla-tion coefficient between the measured value and hyperbolic estimation value was between 0.96 and 0.99,indicating a reliability and high precision of the hyperbolic estimation method.
引文
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[20]王长丹,王旭,周顺华,等.自重湿陷性黄土与单桩负摩阻力离心模型试验[J].岩石力学与工程学报, 2010,29(增刊1):3101-3107.
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[22] Qiu Jun-ling, Wang Xiu-ling, Lai Jin-xing, et al. Response characteristics and preventions for seismic subsidence of loess in Northwest China[J]. Natural Hazards, 2018, 92(7):1-27.
[23]陈希哲.土力学地基基础[M].第4版.北京:清华大学出版社, 2004.
[24]邸道怀.圆形结构下筏式基础变形反力分布规律试验研究[J].建筑结构学报, 2005, 26(5):118-124.
[25]何广讷.浅议地基压力扩散角及沉降计算经验系数[J].地基处理, 2010, 21(3):58-60.
[2]牟太平,张嘎,张建民.土坡破坏过程的离心模型试验研究[J].清华大学学报:自然科学版, 2006, 46(9):1522-1525.
[3] Ding Chun-lin, Meng Xiao-hong. Centrifuge model test and field measurement analysis for foundation pit with confined water[J]. Frontiers of Architecture&Civil Engineering in China, 2009, 3(3):299-304.
[4] Wang Xue-fei, Zeng Xiang-wu, Li Jia-le, et al. Lateral bearing capacity of hybrid monopile-friction wheel foundation for offshore wind turbines by centrifuge modelling[J]. Ocean Engineering, 2018, 148(1):182-192.
[5]程嵩,张嘎,郑瑞华,等.地下水开采对桥梁结构影响的离心模型试验研究[J].岩土力学, 2011, 32(6):1781-1786.
[6]裴向军,张硕,黄润秋,等.地下水雍高诱发黄土滑坡离心模型试验研究[J].工程科学与技术, 2018, 50(5):59-67.
[7]张宇亭.水平循环荷载作用下群桩与软粘土相互作用离心模型试验研究[J].水道港口, 2018, 39(2):211-216.
[8]张建红,劳敏慈.非饱和土中水分迁移及污染物扩散的离心模拟[J].岩土工程学报, 2002, 24(5):622-625.
[9]周小文,程展林,孙常青,等.软土地基路堤施工控制的离心模拟试验研究[J].岩土力学, 2009, 30(5):1253-1256.
[10] Yi X W, Ma G W, Fourie A. Centrifuge model studies on the stability of fibre-reinforced cemented paste backfill stopes[J]. Geotextiles&Geomembranes, 2018,46(4):396-401.
[11]吴玮江,谌文武,宋丙辉,等.兰州原状Q2黄土剪切试验研究[J].兰州大学学报:自然科学版, 2012, 48(6):21-25.
[12]冯立,胡炜,张茂省,等.非饱和黄土强度理论的实用化方法研究[J].兰州大学学报:自然科学版, 2018,54(5):619-625.
[13]杨仲康,陈冠,孟兴民,等.基于现场渗透试验的黄土滑坡体入渗特性[J].兰州大学学报:自然科学版,2017, 53(3):285-291.
[14]胡再强,沈珠江,谢定义.结构性黄土渠道浸水变形离心模型试验有限元分析[J].岩土工程学报, 2004,26(5):637-640.
[15]龚成明,程谦恭,刘争平.黄土边坡开挖与支护效应的离心模拟试验研究[J].岩土力学, 2010, 31(11):3481-3486.
[16] Fan Zhong-jie, Kulatilake P H S W, Peng Jian-bing, et al. In-flight excavation of a loess slope in a centrifuge model test[J]. Geotechnical&Geological Engineering,2016, 34(5):1577-1591.
[17]梅源,胡长明,魏弋峰,等. Q2、Q3黄土深堑中高填方地基变形规律离心模型试验研究[J].岩土力学, 2015,36(12):3473-3481.
[18] Ferber V, Thorel L, Khokhar I M, et al. Physical modelling of wetting-induced collapse in embankment base[J]. Geotechnique, 2011, 61(5):409-420.
[19]金松丽,邢义川,赵卫全,等.黄土地基增湿自重湿陷变形特性的离心模型试验[J].人民长江, 2016, 47(9):90-94.
[20]王长丹,王旭,周顺华,等.自重湿陷性黄土与单桩负摩阻力离心模型试验[J].岩石力学与工程学报, 2010,29(增刊1):3101-3107.
[21] Assallay A M, Rogers C D F, Smalley I J. Formation and collapse of metastable particle packings and open structures in loess deposits[J]. Engineering Geology,1997, 48(1/2):101-115.
[22] Qiu Jun-ling, Wang Xiu-ling, Lai Jin-xing, et al. Response characteristics and preventions for seismic subsidence of loess in Northwest China[J]. Natural Hazards, 2018, 92(7):1-27.
[23]陈希哲.土力学地基基础[M].第4版.北京:清华大学出版社, 2004.
[24]邸道怀.圆形结构下筏式基础变形反力分布规律试验研究[J].建筑结构学报, 2005, 26(5):118-124.
[25]何广讷.浅议地基压力扩散角及沉降计算经验系数[J].地基处理, 2010, 21(3):58-60.