Energy-based evaluation method for soil densification effects induced by vibro-compaction of stone columns
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摘要: 采用常规检测手段进行处理地基的工后质检存在时间滞后与空间局部的问题，不能及时反映处理地基的整体加固效果。提出了一种基于能量的碎石桩复合地基桩周土振动加密效果评价方法，为实现桩周土加密效果的准实时评价提供参考。首先，根据地基弹性波传播理论建立振冲施工过程中桩周土吸收波动能量的计算方法，通过不排水动三轴试验建立典型饱和粉砂土基于吸收能量的超静孔压模型，为进一步根据固结理论预测处理后复合地基桩周土密实度提供依据；其次，依托某工程水电站深厚坝基碎石桩处理工程实例，采用桩周土超静孔压峰值和处理后孔隙比两个关键物理量对方法进行了检验，发现与施工现场实测超静孔压和工后质检得到的孔隙比相比，方法的预测精度达到90%左右，说明基于能量的振冲碎石桩加密效果评价方法具有可行性。Abstract: In view of the fact that the conventional ground inspection methods are not suitable for the real-time monitoring and quality check of ground improvements due to the limitations in timely and full-scale inspection, an energy-based evaluation method for soil densification effects induced by vibro-compaction of stone columns is proposed, which can timely estimate the average densification effects of soils between stone columns. Based on the propagation theory of elastic waves in foundation, a calculation procedure of energy absorbed by soils is established, and the corresponding undrained cyclic triaxial tests on a prototype silty sand are conducted to establish the empirical model for generation of the excess pore water pressure. Then a case study of a reservoir dam project is conducted. It is found that, compared with that of the field monitored excess pore water pressure and the final void ratio obtained via post-construction inspection, the prediction accuracy of the proposed method is about 90%, which preliminarily validate the feasibility of the proposed method.
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图 4 粉砂土的超静孔压和累积吸收能量相关关系
Figure 4. Relationship between excess pore pressure and cumulative dissipated energy of silty sand
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图 5 振动和孔压联合监测示意图
Figure 5. Schematic diagram of vibration and pore pressure monitoring
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图 6 土体单元振动速度峰值径向衰减规律
Figure 6. Variation of vibration velocity amplitude with radial distance
表 1 试验用土的主要颗粒粒径及占比
Table 1 Particle sizes and proportion of silty sand
粒径/mm d > 0.1 d < 0.1且d > 0.075 d < 0.075 含量/% 20 35 45 
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[1] 叶观宝, 苌红涛, 徐超, 等. 无填料振冲法在液化粉细砂中的应用研究[J]. 岩土工程学报, 2009, 31(6): 917-921. doi: 10.3321/j.issn:1000-4548.2009.06.016 YE Guanbao, CHANG Hongtao, XU Chao, et al. Application of vibroflotation without backfill in liquefiable silty and fine sand[J]. Chinese Journal of Geotechnical Engineering, 2009, 31(6): 917-921. (in Chinese) doi: 10.3321/j.issn:1000-4548.2009.06.016
[2] 何广讷. 评价土体液化势的能量法[J]. 岩土工程学报, 1981, 3(4): 11-21. doi: 10.3321/j.issn:1000-4548.1981.04.002 HE Guangne. Energy analysis procedure for evaluating soil liquefaction potential[J]. Chinese Journal of Geotechnical Engineering, 1981, 3(4): 11-21. (in Chinese) doi: 10.3321/j.issn:1000-4548.1981.04.002
[3] GREEN R A, MITCHELL J K. Energy-based evaluation and remediation of liquefiable soils[C]// Geotechnical Engineering for Transportation Projects. Los Angeles, 2004.
[4] HOLEYMAN A E. An earthquake engineering approach to vibro-compaction[C]// 14th International Conference on Soil Mechanics and Foundation Engineering, Hamburg, 1999.
[5] NAGY P, PISTROL J, KOPF F, et al. Integrated compaction control based on the motion behavior of a deep vibrator[J]. Transportation Geotechnics, 2021, 28: 100539. doi: 10.1016/j.trgeo.2021.100539
[6] 黄茂松, 陈云敏, 吴世明. 振冲碎石桩加固饱和粉砂粉土地基试验研究[J]. 岩土工程学报, 1992, 14(6): 69-73. doi: 10.3321/j.issn:1000-4548.1992.06.008 HUANG Maosong, CHEN Yunmin, WU Shiming. Strengthening of saturated silty soils by vibro replacement stone columns[J]. Chinese Journal of Geotechnical Engineering, 1992, 14(6): 69-73. (in Chinese) doi: 10.3321/j.issn:1000-4548.1992.06.008
[7] SHENTHAN T, NASHED R, THEVANAYAGAM S, et al. Liquefaction mitigation in silty soils using composite stone columns and dynamic compaction[J]. Earthquake Engineering and Engineering Vibration, 2004, 3(1): 39-50. doi: 10.1007/BF02668849
[8] 王桂萱, 桑野二郎, 竹村次朗. 循环荷载下砂质混合土孔隙水压力特性研究[J]. 岩土工程学报, 2004, 26(4): 541-545. doi: 10.3321/j.issn:1000-4548.2004.04.023 WANG Guixuan, JIRO Kuwano, JIRO Takemura. Study on excess pore water pressures of sands mixed with clays under cyclic loading[J]. Chinese Journal of Geotechnical Engineering, 2004, 26(4): 541-545. (in Chinese) doi: 10.3321/j.issn:1000-4548.2004.04.023
[9] 张建民, 谢定义. 饱和砂土振动孔隙水压力增长的实用算法[J]. 水利学报, 1991, 22(8): 45-51. doi: 10.3321/j.issn:0559-9350.1991.08.007 ZHANG Jianmin, XIE Dingyi. Practical algorithm for increasing vibration pore water pressure in saturated sand[J]. Journal of Hydraulic Engineering, 1991, 22(8): 45-51. (in Chinese) doi: 10.3321/j.issn:0559-9350.1991.08.007
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