Calculation Method of Unsaturated Loess Matrix Suction by In-situ Soaking Test
-
摘要: 精确计算非饱和土渗透系数时需要考虑土体的负孔隙水压力水头值，即基质吸力。然而基质吸力的准确测定有一定难度，通常室内试验与现场测定的结果相差较大，影响实际工程应用。提出一种全新的算法，即利用原位浸水试验数据对土体基质吸力进行计算，利用Green-Ampt入渗模型结合浸水坑水面下降速率和水分传感器测定的浸水渗透速率之间的差值计算出地层负孔隙压力水头值。选取黄土–古土壤互层场地开展原位浸水试验，根据试验数据计算出第一层厚度为4 m的黄土的负孔隙压力水头值为233 cm，第二层为厚度2 m的古土壤层的负孔隙压力水头值为124 cm；应用该算法预测出在浸水坑以下8.4 m处地层基质吸力消减为零。本研究是对黄土地层基质吸力计算的一种新尝试。Abstract: When the permeability coefficient of unsaturated soil is calculated by a relatively accurate algorithm considering the suction head value of the soil matrix in the project, it is difficult to accurately measure the suction head value of the matrix, and the measurement results of the laboratory test are quite different from the head value measured in the field. A new algorithm was used to calculate the soil matrix suction by using the in-situ water immersion test data. It is different from various traditional testing methods such as the indoor tensiometer method. Instead, it uses the Green-Ampt infiltration model combined with the immersion pit. The suction head value of the formation matrix is calculated from the difference between the water surface falling rate and the water infiltration rate measured by the moisture sensor. Select a loess paleosol interlayer site for in-situ immersion testing. The suction head value of the first layer of loess matrix with a thickness of 4 meters is 233 cm, and the value of the second layer of paleosol with a thickness of 2 meters is 124 cm. Using this algorithm, the suction head value of each layer of soil matrix can be predicted and calculated, and finally it is predicted that the suction of the stratum matrix will decrease to zero at 8.4 m below the immersion pit. This is a new attempt to calculate the suction of soil matrix in loess strata.
-
Key words:
- loess /
- matrix suction /
- immersion test
-
表 1 各层土壤物理指标
地层序号 土层性质 底面深度/m 干重度/(g·cm−3 ) 含水量/% 孔隙比
e饱和度
Sr1 黄土 4.0 1.265 15.9 1.153 0.38 2 古土壤 6.1 1.398 15.0 1.126 0.40 3 黄土 8.4 1.316 13.4 1.042 0.53 4 古土壤 9.4 1.357 16.6 0.996 0.36 5 黄土 13.4 1.388 17.2 0.904 0.33 6 古土壤 14.8 1.428 18.9 1.018 0.41 7 黄土 20.6 1.378 22.2 0.744 0.55 8 古土壤 23.0 1.428 21.0 0.919 0.64 9 黄土 30.0 1.449 21.1 0.855 0.78 
下载: 导出CSV
-
[1] LLORET-CABOT M,WHEELER S J,SÁNCHEZ M. A unified mechanical and retention model for saturated and unsaturated soil behaviour[J]. Acta Geotechnica,2017,12(1):1-21. doi: 10.1007/s11440-016-0497-x [2] 李修磊,陈洪凯,李金凤,等. 基于非饱和土强度理论的土质边坡浅层破坏稳定性分析[J]. 工程科学与技术,2019,51(2):61-70. [3] 赵永富,田恩龙,张国栋. 达西定律与渗流控制[J]. 黑龙江水利科技,2008,36(4):65. doi: 10.14122/j.cnki.hskj.2008.04.040 [4] 胡剑峰,左亚西,夏卫新. 达西定律在工程实际中的应用[J]. 建筑工程技术与设计,2017,(27):2357-2357,1262. [5] 陈 可. 全基质吸力范围的非饱和土持水特性及渗透系数模型研究[D]. 长沙: 湖南大学, 2020. [6] LI P,LI T L,WANG H,et al. Unsaturated loess soil-water characteristic curve and permeability coefficient Childs & Collis-Geroge model prediction[J]. Geotechnical Mechanics,2013,(S2):184-189. [7] ZHANG A J,WANG Y G,XING Y C,et al. Fitting models for soil-water characteristic curve of total and matrix suctions of Yili loess[J]. Chinese Journal of Geotechnical Engineering,2017,16(4):116-125. [8] 吴珺华,杨 松. 滤纸法测定干湿循环下膨胀土基质吸力变化规律[J]. 农业工程学报,2017,33(15):126-132. doi: 10.11975/j.issn.1002-6819.2017.15.016 [9] 吴珺华,杨 松. 干湿循环下膨胀土基质吸力测定及其对抗剪强度影响试验研究[J]. 岩土力学,2017,38(3):678-684. [10] 辛保泉,段正肖,万 露. 滤纸法测定尾矿砂基质吸力试验研究[J]. 长江科学院院报,2020,37(7):125-129. doi: 10.11988/ckyyb.20190289 [11] WU J H,PENG D B,YUAN J P,et al. Research on total suction of expansive soil measured by filter paper method and prediction of matrix suction[J]. Chinese Journal of Disaster Prevention and Mitigation Engineering,2018,38(3):570-574. [12] 王雪冬,李世宇,孙延峰,等. 考虑非饱和浸润层厚度和累积入渗量的改进Green-Ampt模型[J]. 水文地质工程地质,2021,48(6):64-71. doi: 10.16030/j.cnki.issn.1000-3665.202012045 [13] 李 毅,王全九,邵明安,等. Green-Ampt入渗模型及其应用[J]. 西北农林科技大学学报(自然科学版),2007,35(2):225-230. -
图(6) / 表(1)
计量
- 文章访问数: 71
- HTML全文浏览量: 12
- PDF下载量: 17
- 被引次数: 0
