Application and Analysis of Bagged Sand Well in Soft Soil Foundation Treatment of Highway
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摘要: 以广东佛山某公路工程为依托，依据现场监测数据，分析了采用袋装砂井堆载预压法的软基段从堆载至恒载过程中，地表沉降、分层沉降、深层侧向位移和孔隙水压力的变化规律，并结合推算的工后沉降来评价该方法的处理效果。结果表明：在堆载至第210 d时，地表最大沉降量为291 mm，且地表最大沉降速率为8.67 mm/d，小于规范所限定的10 mm/d；软土分层沉降主要发生在深度2～6 m范围内的土层；而软土侧向水平位移主要发生在深度6 m以上的土层中，占到总位移量的约95%；在整个填土预压过程中综合孔压系数B最大值为0.371，小于规范限定的0.4；使用双曲线法对软土路基进行最终沉降及工后沉降推算，其工后沉降控制在34～64 mm之间，小于规范限定的200 mm。研究成果可为本区域公路软土地基的设计和施工提供依据。Abstract: Based on a highway project in Foshan, Guangdong Province, the in-situ monitoring data with bagged sand well surcharge precompression method were aquired from heap load to dead load, and the variation of surface settlement, stratified settlement, deep lateral displacement and pore water pressure in the soft foundation section were analyzed. The treatment effect of this method combined with the calculated post-construction settlement was also evaluated. The results show that the maximum settlement of the surface is 291 mm when the soft foundation loaded by 210 days, and the maximum settlement rate of the surface is 8.67 mm/d, which is less than the 10 mm/d limited by the standard. The stratified settlement of soft soil mainly occurs in the soil layer with a depth of 2～6 m, and the lateral horizontal displacement of the soft soil mainly occurs in the soil layer with a depth of more than 6 m, accounting for about 95% of the total displacement. In the whole process of filling preloading, the maximum comprehensive pore pressure coefficient B is 0.371, which is smaller than the 0.4 limited by the standard. The final settlement and post-construction settlement of soft soil subgrade are calculated by hyperbolic method. The post-construction settlement is controlled between 34～64 mm, which is less than the 200 mm limited by the standard. The research results can provide the basis for the design and construction of highway soft soil foundation in this area.
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表 1 软土层的基本物理力学性质表
断面
桩号含水率/
%湿密度/
(g·cm−3)孔隙比 液限/
%塑限/
%塑性
指数液性
指数压缩系数/
MPa−1压缩模量/
MPa黏聚力/
kPa内摩擦角/
（°）K35+000 72.2 1.58 1.987 42.6 27.9 14.7 2.38 1.829 1.74 3.3 3.1 K35+200 70.4 1.65 1.954 41.4 26.4 13.8 1.99 1.944 2.21 4.5 3.9 K35+400 69.8 1.62 1.921 40.3 25.8 12.9 2.15 1.874 2.39 4.1 2.9 
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表 2 各断面处理情况
断面里程 软土层厚/m 路基填高/m 处理深度/m K35+000 8.54 1.68 13.4 K35+200 8.24 1.59 12.6 K35+400 7.97 1.55 11.8
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表 3 分层沉降分析表
断面里程 磁环
编号地表总
沉降/mm初始磁环
距离/m磁环下
沉量/mm磁环间压
缩量/mm磁环间单位压缩量/(mm·m−1) 占总压缩量
比例/%K35+000 ① 291 2.0 267 24 12 8.2 ② 4.0 191 76 38 26.1 ③ 6.0 111 80 40 27.5 ④ 8.0 70 41 20.5 14 K35+200 ① 256 2.0 233 23 11.5 8.9 ② 4.0 169 64 32 25 ③ 6.0 113 56 28 21.8 ④ 8.0 68 45 22.5 17.5 K35+400 ① 213 2.0 191 22 11 10.3 ② 4.0 123 68 34 31.9 ③ 6.0 88 35 17.5 16.4 ④ 8.0 68 20 10 9.3
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表 4 双曲线法推算最终沉降量及工后沉降量
监测断面 堆载时间/d 实测沉降量/mm 推算结果 α β s∞/mm s工后/mm 相关系数R2 K35+000 210 291 1.0000 0.0173 355.429 64.429 0.941 K35+200 210 256 1.0000 0.0288 290.714 34.714 0.902 K35+400 210 212 0.4167 0.0156 276.053 64.053 0.932
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[1] 刘汉龙,赵明华. 地基处理研究进展[J]. 土木工程学报,2016,49(1):96-115. [2] 万 样,席宁中,于海成. 间接分级接力式排水固结法软基处理试验研究[J]. 建筑科学,2018,34(5):76-81. [3] 张 明,梁天义. 堆载预压法在公路软基试验段处理中的研究[J]. 河南工程学院学报(自然科学版),2018,30(4):38-43. [4] 曹 杰,郑建国,刘 智,等. 真空预压法处理软土地基的工程应用[J]. 岩土工程学报,2017,39(S2):124-127. [5] 陈春珍. 袋装砂井在道路软土地基处理中的应用及监测分析[J]. 中国标准化,2017,(12):205-206. doi: 10.3969/j.issn.1002-5944.2017.12.129 [6] 刘热强,蒋建清. 海相软土地基的塑料排水板和袋装砂井联合堆载预压加固方法[J]. 公路,2015,60(4):42-49. [7] 王美华,王新新. 土体分层沉降监测技术的现状与发展趋势[J]. 建筑施工,2016,38(2):232-234. [8] 邓 锐,李海红. 深层侧向位移监测技术在滑坡监测中的应用案例[J]. 公路,2016,61(9):293-296. [9] GUO X,BAROTH J,DIAS D,et al. An analytical model for the monitoring of pore water pressure inside embankment dams[J]. Engineering Structures,2018,160:356-365. doi: 10.1016/j.engstruct.2018.01.054 [10] 梁滨波. 薄层轮加法在高速公路软土地基施工中的应用[J]. 国防交通工程与技术,2009,7(5):57-58, 64. doi: 10.3969/j.issn.1672-3953.2009.05.017 [11] YIN L,SUN X,YANG P,et al. Stability analysis for subgrade settlement prediction by curve fitting methods[J]. IOP Conference Series: Earth and Environmental Science,2018,170(3):032050. [12] 舒梦雪. 修正指数曲线法在软土路基沉降预测中的应用[J]. 交通科技,2014,(1):61-64. doi: 10.3963/j.issn.1671-7570.2014.01.021 [13] 谢浩岩,朱大伟,王 雷,等. 基于地基沉降速率法的老路拓宽控制指标分析[J]. 现代交通技术,2014,11(3):5-8. [14] 饶为国,杜文锋,罗卫东,等. 三点法推算桩—网复合路基工后沉降量[J]. 公路,2001,(8):92-95. doi: 10.3969/j.issn.0451-0712.2001.08.026 [15] 谭志华. 泊松法预测路基沉降[J]. 广东建材,2009,25(6):27-29. doi: 10.3969/j.issn.1009-4806.2009.06.010 -
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