Feasibility of predicting settlement of medium compression soil foundation with centrifuge model tests
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摘要: 应用TLJ-2型土工离心试验机, 采用停机加载法与变加速度加载法, 研究了海南东环客运专线和胶济客运专线中等压缩性土地基的沉降特性, 并与现场填筑试验结果进行了对比, 分析了应用离心模型试验方法预测原型地基沉降的主要影响因素与预测精度。研究结果表明: 采用2种离心模型试验方法所得地基沉降比现场填筑试验值大, 且随着地基深度增大, 沉降修正系数减小, 沉降差异增大; 在现场填筑试验中, 地基表层6.0m范围内产生的沉降占地基总沉降的比例大于45%, 而离心模型试验的比例小于20%;2种离心模型试验方法产生的地基沉降具有相似的沉降特性, 路基填筑期完成的沉降占总沉降比例相同, 均为88%, 但采用停机加载法产生的地基沉降比变加速度法大1倍左右。可见, 采用2种离心模型试验方法均较难预测原型中等压缩性土地基的沉降, 但可进行定性分析。Abstract: Centrifuge-stopped loading method and acceleration-variable centrifuge-run loading method were carried out by using TLJ-2 geotechnical centrifuge, the settlement characteristics of medium compression soil foundations of Haidong High-speed Railway and Jiaoji High-speed Railway were researched and compared with that of field-filling tests, and the main factors influencing the precisions of predicting prototype foundation settlement with centrifuge tests were studied.Research result indicates that the settlements from centrifuge tests are larger than that from filling tests, and their correction factors decrease and the settlement differences increase with the increase of foundation depth.The settlements within 6.0 m from filling tests are more than 45% of total settlement, but the settlements from centrifuge tests are less than 20% of total settlement.The properties of the settlements from two centrifuge tests are similar, the settlements in subgrade filling are 88% of total settlements, but the settlement from the first method is about twice of that from the second method.Obviously, it is very hard to predict the foundation settlement of medium compression soil by using centrifuge tests, but the tests can be used for qualitative analysis.
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图 6 未扣除加载期沉降时荷载、沉降与时间关系
Figure 6. Relationships of loads, settlements and time with loading stage's settlements
图 7 扣除加载期沉降后荷载、沉降与时间关系
Figure 7. Relationships of loads, settlements and time without loading stage's settlements
表 1 地基土物理参数
Table 1. Physical parameters of foundation soils
断面 土名 参数 深度/m 含水量/% 干密度/(g·cm-3) DK67+620(停机加载法) 花岗岩全风化土(1) 0~6.0 26.52 1.53 花岗岩全风化土(2) 6.0~18.0 28.01 1.52 花岗岩全风化土(3) 18.0~24.0 35.37 1.46 DK67+630(变加速度加载法) 花岗岩全风化土(1) 0~6.0 25.45 1.55 花岗岩全风化土(2) 6.0~15.0 27.88 1.53 花岗岩全风化土(3) 15.0~21.0 32.08 1.49 DK218+950(停机加载法) 粉质粘土 0~11.2 9.11 1.80 粉土 11.2~18.2 14.98 1.70 黄土质粉质粘土 18.2~28.1 19.85 1.65 DK218+950(变加速度加载法) 粉质粘土 0~11.2 9.35 1.80 粉土 11.2~18.2 14.63 1.71 黄土质粉质粘土 18.2~28.1 19.94 1.65 
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表 2 恒载期地基应力对比
Table 2. Comparison of foundation stresses under constant loads
海东线 DK67+620(停机加载法) DK67+630(变加速度加载法) 距地基面深度/cm 0 3.8 8.0 0 4.0 8.0 地基应力/kPa 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 施加的路基荷载 第1级 24.0 0.0 65.4 42.6 114.4 91.2 20.4 0.0 33.0 11.3 44.5 22.9 第2级 41.4 0.0 82.1 42.6 128.3 91.2 34.7 0.0 52.5 22.4 70.2 45.6 第3级 57.3 0.0 96.1 42.6 139.5 91.2 53.4 0.0 81.5 33.7 108.3 68.4 第4级 82.6 0.0 118.0 42.6 158.1 91.2 79.5 0.0 117.0 45.0 154.4 91.3 胶济线 DK218+950(停机加载法) DK218+950(变加速度加载法) 距地基面深度/cm 0 4.0 14.7 0 4.0 14.7 地基应力/kPa 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 总应力 自重应力 施加的路基荷载 第1级 31.2 0.0 87.7 61.8 244.9 236.1 26.5 0.0 38.1 15.5 71.7 59.0 第2级 73.4 0.0 126.6 61.8 279.8 236.1 56.9 0.0 82.4 30.8 154.1 117.7 第3级 88.9 0.0 141.7 61.8 283.4 236.1 81.0 0.0 119.6 46.2 220.0 176.6 第4级 103.6 0.0 153.2 61.8 288.0 236.1 99.7 0.0 152.3 61.6 294.5 235.4
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表 3 地基沉降对比
Table 3. Comparison of foundation settlements
试验断面 距地基面深度/m 离心模型试验 现场填筑试验[12] 沉降修正系数 未扣除加载期沉降 扣除加载期沉降 总沉降/mm 填筑期沉降占总沉降比例/% 未扣除加载期沉降 扣除加载期沉降 总沉降/mm 填筑期沉降占总沉降比例/% 总沉降/mm 填筑期沉降占总沉降比例/% 海东线DK67+620(停机加载法) 0 808.2 89 173.7 51 123.0 95 0.15 0.71 6.0 660.0 88 153.5 48 56.0 93 0.09 0.36 10.5 526.3 87 124.8 43 40.0 93 0.08 0.32 海东线DK67+630(变加速度加载法) 0 420.4 89 154.6 69 114.0 94 0.27 0.74 6.0 355.7 87 129.7 66 62.0 95 0.17 0.48 13.0 270.6 89 98.0 69 40.0 93 0.15 0.41 胶济线DK218+950(停机加载法) 0 438.4 89 107.0 54 96.0 92 0.22 0.90 胶济线DK218+950(变加速度加载法) 0 228.1 88 70.4 61 96.0 92 0.42 1.36 6.4 213.7 88 69.3 59 42.4 94 0.20 0.61 11.0 198.7 86 64.4 60 26.2 94 0.13 0.41
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表 4 地基压缩量对比
Table 4. Comparison of foundation compressions
试验断面 关键参数 离心模型试验 现场填筑试验[12] 未扣除加载期沉降 扣除加载期沉降 海东线DK67+620(停机加载法) 计算深度/m 0~6.0 0~10.5 0~6.0 0~10.5 0~6.0 0~10.5 压缩量占总沉降比例/% 18.3 34.9 11.6 28.2 54.5 67.5 计算深度/m 0~6.0 6.0~10.5 0~6.0 6.0~10.5 0~6.0 6.0~10.5 单位厚度压缩量/mm 24.7 29.7 3.4 6.4 11.2 3.6 海东线DK67+630(变加速度加载法) 计算深度/m 0~6.0 0~13.0 0~6.0 0~13.0 0~6.0 0~13.0 压缩量占总沉降比例/% 15.4 35.6 16.1 36.6 45.6 64.9 计算深度/m 0~6.0 6.0~13.0 0~6.0 6.0~13.0 0~6.0 6.0~13.0 单位厚度压缩量/mm 10.8 12.2 4.2 4.5 8.7 3.1 胶济线DK218+950(变加速度加载法) 计算深度/m 0~6.4 0~11.0 0~6.4 0~11.0 0~6.4 0~11.0 压缩量占总沉降比例/% 6.3 12.9 1.6 8.5 55.8 72.7 计算深度/m 0~6.4 6.4~11.0 0~6.4 6.4~11.0 0~6.4 6.4~11.0 单位厚度压缩量/mm 2.3 3.3 0.2 1.1 8.4 3.5
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[1] 谢永利, 潘秋元, 曾国熙. 应用离心模型试验研究软基变形性状[J]. 岩土工程学报, 1995, 17(4): 45-50. doi: 10.3321/j.issn:1000-4548.1995.04.007XIE Yong-li, PAN Qiu-yuan, ZENG Guo-xi. Study on deformation behavior of soft clay ground with centrifugal model test[J]. Chinese Journal of Geotechnical Engineering, 1995, 17(4): 45-50. (in Chinese) doi: 10.3321/j.issn:1000-4548.1995.04.007 [2] 饶锡保, 龚壁卫, 程展林, 等. 基于离心模型试验的某公路软基沉降变形规律研究[C]∥中国水利学会. 2007学术年会物理模拟技术在岩土工程中的应用. 苏州: 中国水利学会, 2007: 119-125.RAO Xi-bao, GONG Bi-wei, CHENG Zhan-lin, et al. Study on deformation behavior of a highway embankment on softclay with centrifugal model test[C]∥Chinese Hydraulic Engineering Society. Proceedings of 2007 annual conference of physical simulation techniques in geotechnical engineering. Suzhou: Chinese Hydraulic Engineering Society, 2007: 119-125. (in Chinese) [3] 章为民, 徐光明. 土石坝填筑过程的离心模拟方法[J]. 水利学报, 1997(2): 8-13. doi: 10.3321/j.issn:0559-9350.1997.02.002ZHANG Wei-min, XU Guang-ming. Study on modeling the construction process of embankment dams in centrifugal test[J]. Journal of Hydraulic Engineering, 1997(2): 8-13. (in Chinese) doi: 10.3321/j.issn:0559-9350.1997.02.002 [4] 丁金华, 包承纲. 软基和吹填土上加筋堤的离心模型试验及有限元分析[J]. 土木工程学报, 1999, 32(1): 21-25. doi: 10.3321/j.issn:1000-131X.1999.01.004DING Jin-hua, BAO Cheng-gang. Centrifugal model test and finite element analysis of geosynthetic reinforced embankments on soft ground and dredger fill[J]. China Civil Engineering Journal, 1999, 32(1): 21-25. (in Chinese) doi: 10.3321/j.issn:1000-131X.1999.01.004 [5] 陈胜立, 张丙印, 张建民, 等. 软基上加筋防波堤的离心模型试验[J]. 岩石力学与工程学报, 2005, 24(15): 2751-2756. doi: 10.3321/j.issn:1000-6915.2005.15.026CHEN Sheng-li, ZHANG Bing-yin, ZHANG Jian-min, et al. Centrifugal modeling of reinforced embankments on soft clay[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(15): 2751-2756. (in Chinese) doi: 10.3321/j.issn:1000-6915.2005.15.026 [6] 卢国胜, 蒋昌贵, 王迅. 搅拌桩处理软土地基的离心机试验研究[J]. 岩土力学, 2007, 28(10): 2101-2105. doi: 10.3969/j.issn.1000-7598.2007.10.018LU Guo-sheng, JIANG Chang-gui, WANG Xun. Centrifuge experiment study on mixing pile improving soft foundation[J]. Rock and Soil Mechanics, 2007, 28(10): 2101-2105. (in Chinese) doi: 10.3969/j.issn.1000-7598.2007.10.018 [7] WANG Chang-dan, WANG Bing-long, WANG Xu, et al. Centrifugal model tests on settlement controlling of piled embankment in high speed railway[C]∥MAO Bao-hua, TIAN Zong-zhou, HUANG Hai-jun, et al. Traffic and Transportation Studies(ICTTS2010). Kunming: ASCE, 2010: 1407-1416. [8] BASSETT R H, HORNER J. Prototype deformations from centrifugal model tests[C]∥TELFORD T. Proceedings of the 7th European Conference on Soil Mechanics and Foundation Engineering. Brighton: Springerlink, 1979: 1-9. [9] DAVIES M C R, PARRY R H G. Centrifuge modelling of embankments on clay foundations[J]. Soils and Foundations, 1985, 25(4): 19-36. [10] SHARMA J S, BOLTON M D. Finite element analysis of centrifuge tests on reinforced embankments on soft clay[J]. Computers and Geotechnics, 1996, 19(1): 1-22. doi: 10.1016/0266-352X(95)00037-B [11] ALLERSMA H G B, LEE S W, LEE Y N. Centrifuge modeling of embankment construction by the dumping method onsoft soil[C]∥HANSON J L, TERMAAT R J. Soft GroundTechnology. Noordwijkerhout: ASCE, 2000: 423-434. [12] 中铁二院工程集团有限责任公司, 西南交通大学. 客运专线中等压缩性土地基沉降特性及处理技术研究总报告[R]. 成都: 中铁二院工程集团有限责任公司, 2010.China Railway Eryuan Engineering Group Co., Ltd., Southwest Jiaotong University. Study on settlement and composite treatment of medium compression soil foundation for high-speed railway[R]. Chengdu: China Railway Eryuan Engineering Group Co., Ltd., 2010. (in Chinese) [13] 王景芝, 李安洪, 肖红兵, 等. 饱和全风化花岗岩地基土压缩特性的研究[J]. 铁道建筑, 2009(6): 73-76. https://www.cnki.com.cn/Article/CJFDTOTAL-TDJZ200906027.htmWANG Jing-zhi, LI An-hong, XIAO Hong-bing, et al. Study of compression characteristics of saturated completely decomposed granite foundation[J]. Railway Engineering, 2009(6): 73-76. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-TDJZ200906027.htm [14] 吴丽君, 蒋关鲁, 李安洪, 等. 非饱和粉质粘土固结压缩特性及体变试验研究[J]. 现代地质, 2009, 23(3): 559-563. doi: 10.3969/j.issn.1000-8527.2009.03.023WU Li-jun, JIANG Guan-lu, LI An-hong, et al. Consolidation and compressibility of unsaturated silt clay and test study on volume change[J]. Geoscience, 2009, 23(3): 559-563. (in Chinese) doi: 10.3969/j.issn.1000-8527.2009.03.023 -
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