饱和黏土中的孔压传递过程是进行岩土工程问题机理分析的基础,其在传递过程中是否有滞后及所涉影响因素一直备受关注。对此,设计了一套测试装置,对经固结的饱和黏土施加水压进行孔压传递测试,并在此基础上开展数值仿真分析。试验发现饱和黏土中的孔压传递存在明显滞后现象,且固结压力越大,滞后时间越长;建立的数值仿真模型模拟了孔压传递过程,分析发现孔隙水压缩系数和土体渗透系数是孔压传递滞后的主要影响因素。进一步运用数值仿真手段对这2种影响因素进行参数分析,结果表明:孔压传递滞后时长总体随孔隙水压缩系数的增大或土体渗透系数的减小而增长,尤其在孔隙水压缩系数>10-5 kPa-1、土体渗透系数＜10-8 m/s的情况下,滞后时长的变幅剧烈。
Abstract
The transmission of pore water pressure in saturated clay is the foundation for analyzing geotechnical engineering problems. Delays in the transmission process and factors influencing the delay have attracted wide attentions. A testing apparatus was designed to examine the transfer of pore pressure by applying hydraulic pressure to consolidated saturated clay. Subsequently, a numerical model was established to simulate the transfer process of pore water pressure. The results reveal noticeable hysteresis in the transmission of pore pressure in saturated clay, with the duration of hysteresis increasing in proportion to the consolidation pressure. Pore water compression coefficient and soil permeability coefficient are primary factors affecting the hysteresis of pore water pressure transfer. Additionally, further numerical simulations demonstrate that an increase in pore water compression coefficient or a decrease in soil permeability leads to an extended lag time in pore pressure transfer. Specifically, when the pore water compression coefficient exceeds 10-5 kPa-1 and the soil permeability coefficient is lower than 10-8 m/s, the lag time variations become more pronounced.
关键词
饱和黏土 /
孔压传递 /
滞后时长 /
孔隙水压缩系数 /
渗透系数
Key words
saturated clay /
pore pressure transfer /
hysteresis time /
pore water compression coefficient /
permeability coefficient
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参考文献
[1] 魏新江,张 涛,丁 智,等.地铁荷载下不同固结度软黏土的孔压试验模型[J].岩土力学,2014,35(10):2761-2768,2874.(WEI Xin-jiang,ZHANG Tao,DING Zhi,et al. Experimental Study of Pore Pressure Model of Soft Clay with Different Consolidation Degrees under Subway Loading[J]. Rock and Soil Mechanics,2014,35(10):2761-2768,2874.(in Chinese))
[2] MUSKAT M. The Flow of Homogeneous Fluids through Porous Media[J]. Soil Science, 1938, 46(2): 169.
[3] RICHARDS A F, ØTEN K, KELLER G H, et al. Differential Piezometer Probe for an in Situ Measurement of Sea-floor[J]. Géotechnique, 1975, 25(2): 229-238.
[4] BENNETT R H, BRYANT W R, DUNLAP W A, et al. Initial Results and Progress of the Mississippi Delta Sediment Pore Water Pressure Experiment[J]. Marine Geotechnology, 1976, 1(4): 327-335.
[5] OKUSA S,UCHIDA A.Pore-water Pressure Change in Submarine Sediments Due to Waves[J]. Marine Geotechnology,1980,4(2):145-161.
[6] RAYNAUD S, VASSEUR G, CÉLÉRIER B, et al. Experimental Study of the Relation between the Permeability of Kaolinite and Its Deformation at Micro and Macro Scale[J]. International Journal of Rock Mechanics and Mining Sciences,2010,47(4):559-567.
[7] ABDOLLAHI A, MASON H B. Pore Water Pressure Response during Tsunami Loading[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2020, 146(3): 04020004.
[8] 唐益群, 张 曦, 赵书凯, 等. 地铁振动荷载下隧道周围饱和软黏土的孔压发展模型[J]. 土木工程学报, 2007, 40(4): 82-86.(TANG Yi-qun, ZHANG Xi, ZHAO Shu-kai, et al. Model of Pore Water Pressure Development in Saturated Soft Clay around a Subway Tunnel under Vibration Load[J]. China Civil Engineering Journal, 2007, 40(4): 82-86.(in Chinese))
[9] 倪春海, 宋林辉, 王宇豪, 等. 不同水压下的黏土孔压传递规律试验[J]. 南京工业大学学报(自然科学版), 2016, 38(1): 68-73, 82.(NI Chun-hai, SONG Lin-hui, WANG Yu-hao, et al. Experimental Study on Pore Pressure Transmission Law of Clay under Various Water Pressures[J]. Journal of Nanjing TECH University (Natural Science Edition), 2016, 38(1): 68-73, 82.(in Chinese))
[10] 牛 顺, 肖 涛, 冯健雪, 等. 考虑扰动效应的透水管桩地基土固结效果有限元分析[J]. 长江科学院院报, 2021, 38(12): 130-136, 145.(NIU Shun, XIAO Tao, FENG Jian-xue, et al. Finite Element Analysis of Consolidation Effectiveness of Soil Foundation of Permeable Pipe Pile in Consideration of Disturbance Effect[J]. Journal of Yangtze River Scientific Research Institute, 2021, 38(12): 130-136, 145.(in Chinese))
[11] 赵慈义, 孙 雯, 陈守义, 等. 孔隙水压力量测的延迟效应分析[J]. 岩土力学, 1995, 16(4): 66-73.(ZHAO Ci-yi, SUN Wen, CHEN Shou-yi, et al. An Analysis on the Delay Effect in Pore Water Pressure Measurement[J]. Rock and Soil Mechanics, 1995, 16(4): 66-73.(in Chinese))
[12] 问延煦,施建勇.孔压滞后现象及其对固结系数的影响[J].岩石力学与工程学报,2005,24(2):357-364.(WEN Yan-xu,SHI Jian-yong.Delay of Pore Pressure in Oedometer and Its Effect on Determination of Coefficient of Consolidation[J]. Chinese Journal of Rock Mechanics and Engineering,2005,24(2):357-364.(in Chinese))
[13] TANG L, CHEN H, SONG J. Process of Pore Pressure Diffusion in Saturated Clay Soil and Impact of Adsorbed Water[J]. Geosciences Journal, 2016, 20(5): 649-665.
[14] 刘 侃,朱小军,张帆舸,等. 含气泡土的孔隙流体压缩系数计算分析[J]. 岩土工程学报,2017,39(增刊2): 120-123.(LIU Kan, ZHU Xiao-jun, ZHANG Fan-ge, et al. Calculation of Coefficient of Compressibility for Air-water Mixture in Gassy Soils[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(Sup.2): 120-123.(in Chinese))
[15] FREDLUND D G, RAHARDJO H, FREDLUND M D. Unsaturated Soil Mechanics in Engineering Practice[M]. Hoboken: Wiley, 2012.
[16] WHEELER S J. The Undrained Shear Strength of Soils Containing Large Gas Bubbles[J]. Géotechnique, 1988, 38(3): 399-413.
基金
国家自然科学基金面上项目(51578164);江苏省研究生科研与实践创新计划项目(KYCX22-1280)
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