EXPERIMENTAL STUDY ON PRINCIPLE, METHOD AND APPLICABILITY OF IN-SITU MEASUREMENT OF LOESS GAS PERMEABILITY COEF ̄FI ̄CIENT
-
摘要: 渗透系数是黄土渗透变形破坏及黄土水理性质相关研究中的一项重要参数,而渗气系数与渗透系数具有良好的相关性且其测试过程不受黄土水敏性的影响,同时比渗透系数测定更为方便和快捷,因此具有良好的推广应用前景。本文介绍了黄土原位渗气测试方法的原理,在此基础上针对插入式和接触式两种原位渗气测试方法,在不同地区黄土地层开展了一系列原位渗气测试。试验结果发现两种方法对黄土地层的适用性有所不同,插入式方法十分适用于黏粒含量大于12.44%(塑性指数大于11.2)的黄土层,但对于黏粒含量低于12.44%(塑性指数小于11.2)的黄土层,插入式方法则会产生较大的误差。经综合对比认为,接触式方法由于人为误差小而普遍适用于黄土地层,但需要更大的工作面且更适于水平工作面,这对其测试速度和便捷性有一定影响。插入式方法所需工作面小,且同时适合水平和垂直工作面,因此更为方便快捷,但由于插入过程中探头对黄土层的扰动等人为因素的影响,因此更适合黏粒含量较高的黄土层。建议当黄土黏粒含量大于12.44%(塑性指数大于11.2)时,首选插入式方法,不满足此条件时再采用接触式方法。本文介绍的两种黄土原位渗气系数测定方法及其适用范围的确定为其在实践中进一步推广应用提供了理论基础。Abstract: The permeability coefficient is an important parameter in the study of loess seepage deformation and loess hydraulic properties. However,the gas permeability coefficient has a good correlation with the permeability coefficient,and water sensitivity of loess can not affect its testing process. At the same time,it is more convenient and faster than the determination of permeability coefficient. So it has a good prospect of popularization and application. This paper introduces the principle of loess in-situ gas permeability test method. On this basis,we carry a series of in-situ gas permeability tests in different loess areas by contact type and plug-in type. The test results show that the two methods have different application scopes for loess stratum. The plug-in method is more suitable when the clay content of loess is greater than 12.44%(the plasticity index is greater than 11.2). On the contrary,when the clay content is less than 12.44%(the plasticity index is less than 11.2),the plug-in method can cause larger errors. The comprehensive comparison shows the contact method is generally applicable to loess strata because of its less human error. But this method needs a larger working face and is more suitable for horizontal working face,which affects the test speed and convenience. The plug-in method needs a smaller working face,and is suitable for both horizontal and vertical working face. So it is more convenient and faster. However,the process of probe inserting into loess can cause disturbance,so this method is more suitable for loess layer with higher clay content. When the clay content of loess is greater than 12.44%(the plasticity index is greater than 11.2),we suggest to give priority to the plug-in method. If the site does not meet these conditions,we suggest to choose the contact method. The two determination methods of in-situ gas permeability coefficient of loess and their application scope provide a theoretical basis for further application in practice.
-
Key words:
- Gas permeability /
- In-situ test /
- Contact type /
- Plug type
-
表 1 原状黄土的基本物理指标
Table 1. Basic physical indexes of undisturbed loess
取样地点 取样深度d
/m干密度ρd
/g·cm-3含水率w
/%充气孔隙度n
/cm3·cm-3颗粒组成/% 黏粒<0.005 mm 粉粒0.075~0.005 mm 黏粒0.25~0.075 mm 西安 2.0 1.35 0.89 0.34 12.44 82.09 5.47 4.0 1.41 1.62 0.31 16.18 80.15 3.67 6.0 1.46 2.58 0.29 17.72 79.34 2.94 8.0 1.52 3.24 0.25 20.83 76.52 2.65 10.0 1.58 3.72 0.21 25.29 72.47 2.24 延安 2.0 1.51 0.76 0.44 6.47 78.25 15.28 4.0 1.67 0.80 0.37 9.36 77.78 12.86 6.0 1.53 0.91 0.42 9.89 76.77 13.31 8.0 1.60 1.08 0.39 13.14 71.91 14.95 10.0 1.59 1.22 0.39 19.86 70.37 9.77 黑方台 2.0 1.37 0.68 0.48 7.65 75.43 16.92 4.0 1.41 0.77 0.47 8.69 75.21 16.10 6.0 1.38 0.96 0.47 11.31 76.93 11.76 8.0 1.43 0.63 0.46 8.07 76.27 15.66 10.0 1.42 0.69 0.46 9.39 74.69 15.92 充气孔隙度n为:n=1-$\frac{\rho_{\mathrm{b}}}{\rho_{\mathrm{s}}}$-θv;ρb为土体容重(g·cm-3);ρs为土体颗粒密度(g·cm-3);θv为体积含水率 -
Cao Y, Niu G Y, Wang T L. 2017. In-situ measurement of rock permeability based on pneumatic tests in boreholes[J]. Chinese Journal of Geotechnical Engineering, 39(3): 534-539. Chamberlain E J, Gow A J. 1979. Effect of freezing and thawing on the permeability and structure of soils[J]. Engineering Geology, 13(1-4): 73-92. doi: 10.1016/0013-7952(79)90022-X Chen C L, Zhang D F, Zhang J. 2017. Influence of stress and water content on air permeability of intact loess[J]. Canadian Geotechnical Journal, 54 : 1221-1230. doi: 10.1139/cgj-2016-0186 Ding P R. 1986. The manufacture of type ZC-5 air permeameter and a study on the measurement of air seepage[J]. Journal of Xi'an University of Technology, (4): 37-52. Eijpe R, Weber K J. 1971. Mini-permeameter for consolidated rock and unconsolidated sand[J]. Aapg Bulletin, 55(2): 307-309. Gao Y, Ma Y X, Zhang W Y, et al. 2019. Analysis of humidifying deformation characteristics and microstructure of loess in Xining Area[J]. Journal of Engineering Geology, 27(4): 803-810. Hao Y Z, Wang T H, Jin X, et al. 2020. Experimental study on the saturated compacted loess permeability under K0 consolidation[J]. Advances in Civil Engineering, 2020(2): 1-16. Hong B, Li X A, Wang L, et al. 2019. Permeability anisotropy and microstructure of Yan'an Q3 loess[J]. Journal of Jilin University(Earth Science Edition), 49(5): 1389-1397. Kirkham D. 1947. Field method for determination of air permeability of soil in its undisturbed state[J]. Soil Science Society of America Journal, 11(C): 93-99. doi: 10.2136/sssaj1947.036159950011000C0018x Li X A, Liu J Y, Guo Z Z, et al. 2018. Study on relationship between pore structure parameters and permeability of Malan loess[J]. Journal of Engineering Geology, 26(6): 1415-1423. Li X A, Xue Q, Pang T, et al. 2019. A new in-situ test method of gas permeability and it's utility on the field of suffosion loess[J]. Journal of Engineering Geology, 27(5): 1027-1034. doi: 10.13544/j.cnki.jeg.2019069 Liu J Y, Li X A, Jian T, et al. 2017. A study of the relationship between gas permeability and saturated coefficient of permeability of the Malan loess[J]. Hydrogeology & Engineering Geology, 44(6): 154-162. Mi H Z, Yang Z P. 2011. Experimental study on permeability of three kinds of improved loess[J]. Building Science, 27(11): 41-43. Mohammadi M H, Vanclooster M. 2019. A simple device for field and laboratory measurements of soil air permeability[J]. Soil Science Society of America Journal, 83(1): 58-63. doi: 10.2136/sssaj2018.03.0114 Mosley R B, Snoddy R, Brubaker S A, et al. 1996. Experimental evaluation of geometrical shape factors fpr short cylindrical probes used to measure soil permeability to air[J]. Environment International, 22(1): 509-520. https://www.sciencedirect.com/science/article/pii/S0160412096001535 Qin X H, Liu D S, Song Q H, et al. 2017. Experimental study on one-dimensional vertical infiltration in soil column under rainfall and the derivation of permeability coefficient[J]. Chinese Journal of Rock Mechanics and Engineering, 36(2): 475-484. doi: 10.13722/j.cnki.jrme.2016.0068 Shen J, Dong Y S, Jian W B, et al. 2020. Study on evolution process of landslides triggered by typhoon rainstorm[J]. Journal of Engineering Geology, 28(6): 1290-1299. doi: 10.13544/j.cnki.jeg.2019-540 Tuli A, Hopmans J W, Rolston D E, et al. 2005. Comparison of air and water permeability between distured and undistured soils[J]. Soil Science Society of America Journal, 69(5): 1361-1371. doi: 10.2136/sssaj2004.0332 Wang J D, Xu Y J, Zhang D F, et al. 2021. Vibration-induced acceleration of infiltration in loess[J]. Science China Earth Sciences, 64(4): 611-630. doi: 10.1007/s11430-020-9741-x Wang J D, Zhang D F, Chen C L, et al. 2020. Measurement and modelling of stress-dependent water permeability of collapsible loess in China[J]. Engineering Geology, 266: 105393. doi: 10.1016/j.enggeo.2019.105393 Wang Q K, Zhang B, Wang H X, et al. 2020. Optimization and stability analysis of layout parameters of lined high-pressure gas storage caverns[J]. Journal of Engineering Geology, 28(5): 1123-1131. doi: 10.13544/j.cnki.jeg.2020-305 Wang T X, Lu J, Zhang J F. 2006. Experimental study on permeability coefficient of artificially compacted unsaturated loess considering influence of density[J]. Chinese Journal of Rock Mechanics and Engineering, 25(11): 2364-2368. https://oversea.cnki.net/kcms/detail/detail.aspx?dbcode=cjfd&dbname=cjfd2006&filename=YSLX200611034 Xue Q. 2020. Experimental study on air permeability of malan loess and uniformity of reshaped samples based on air permeability[D]. Xi'an: Chang'an University. Yao Z H, Huang X F, Chen Z H, et al. 2012. Comprehensive soaking tests on self-weight collapse loess with heavy section in Lanzhou region[J]. Chinese Journal of Geotechnical Engineering, 34(1): 65-74. http://manu31.magtech.com.cn/Jwk_ytgcxb/EN/Y2012/V34/I1/65 Zhao M, He H. 2005. Experiment on water-air permeability of unsaturated loess[J]. Journal of Xi'an University of Science and Technology, 25(3): 292-295. doi: 10.1007/s10040-018-1861-8 曹渊, 牛冠毅, 王铁良. 2017. 基于钻孔充气试验的岩石渗透率原位测量研究[J]. 岩土工程学报, 39(3): 534-539. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201703025.htm 丁朴荣. 1986. ZC-5型渗气仪的研制与渗气测试方法的研究[J]. 西安理工大学学报, (4): 40-55. https://www.cnki.com.cn/Article/CJFDTOTAL-XALD198604004.htm 高英, 马艳霞, 张吾渝, 等. 2019. 西宁地区黄土增湿变形特性及微观结构分析[J]. 工程地质学报, 27(4): 803-810. doi: 10.13544/j.cnki.jeg.yt2019416 洪勃, 李喜安, 王力, 等. 2019. 延安Q3原状黄土渗透各向异性及微结构分析[J]. 吉林大学学报(地球科学版), 49(5): 1389-1397. https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ201905016.htm 李喜安, 刘锦阳, 郭泽泽, 等. 2018. 马兰黄土孔隙结构参数与渗透性关系研究[J]. 工程地质学报, 26(6): 1415-1423. doi: 10.13544/j.cnki.jeg.2017-551 李喜安, 薛泉, 庞涛, 等. 2019. 基于原位渗气试验的黄土潜蚀地层渗气率研究[J]. 工程地质学报, 27(5): 1027-1034. doi: 10.13544/j.cnki.jeg.2019069 刘锦阳, 李喜安, 简涛, 等. 2017. 马兰黄土渗气率与饱和渗透系数的关系研究[J]. 水文地质工程地质, 44(6): 154-162. https://www.cnki.com.cn/Article/CJFDTOTAL-SWDG201706025.htm 米海珍, 杨泽平. 2011.3种改良土的渗透性试验研究[J]. 建筑科学, 27(11): 41-43. doi: 10.3969/j.issn.1002-8528.2011.11.010 沈佳, 董岩松, 简文彬, 等. 2020. 台风暴雨型土质滑坡演化过程研究[J]. 工程地质学报, 28(6): 1290-1299. doi: 10.13544/j.cnki.jeg.2019-540 覃小华, 刘东升, 宋强辉, 等. 2017. 降雨条件下一维土柱垂直入渗模型试验研究及其渗透系数求解[J]. 岩石力学与工程学报, 36(2): 475-484. https://www.cnki.com.cn/Article/CJFDTOTAL-YSLX201702019.htm 王家鼎, 许元珺, 张登飞, 等. 2021. 黄土振动促渗效应研究[J]. 中国科学: 地球科学, 51(5): 763-782. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK202105010.htm 王其宽, 张彬, 王汉勋, 等. 2020. 内衬式高压储气库群布局参数优化及稳定性分析[J]. 工程地质学报, 28(5): 1123-1131. doi: 10.13544/j.cnki.jeg.2020-305 王铁行, 卢靖, 张建锋. 2006. 考虑干密度影响的人工压实非饱和黄土渗透系数的试验研究[J]. 岩石力学与工程学报, 25(11): 2364-2368. doi: 10.3321/j.issn:1000-6915.2006.11.030 薛泉. 2020. 马兰黄土渗气率及基于渗气率的重塑试样均匀性研究[D]. 西安: 长安大学. 姚志华, 黄雪峰, 陈正汉, 等. 2012. 兰州地区大厚度自重湿陷性黄土场地浸水试验综合观测研究[J]. 岩土工程学报, 34(1): 65-74. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201201003.htm 赵敏, 何晖. 2005. 非饱和黄土水-气渗透性试验研究[J]. 西安科技大学学报, 25(3): 292-295. doi: 10.3969/j.issn.1672-9315.2005.03.006 -