Experimental study on wetting deformation characteristics of gravelly soil core materials
-
摘要: 针对砾石土心墙料,采用大型应力式三轴仪开展了单线法湿化变形试验,较系统地研究了湿化应变与应力水平、围压之间的变化规律。依据试验成果,砾石土心墙料的湿化变形是明显的,且与应力水平、围压密切相关,在高围压、高应力水平条件下,外力改变了试样的饱和状态,砾石土样品逐渐从非饱和状态过渡到饱和状态,砾石土料存在应力饱和现象,导致湿化过程中没有明显的湿化变形。当围压较小时,湿化应变随应力水平的增大而增大,当围压增大到一定量值时,湿化应变反而随应力水平的增大而减小,呈现明显的分叉现象,表现出更加复杂的规律。最后提出了砾石土料湿化变形模型及模型参数,提出的砾石土料湿化模型可作为高土石坝湿化变形分析的基础。Abstract: A series of single-line wetting deformation tests are carried out on the gravelly soil core materials using a large stress triaxial apparatus to systematically investigate the variation of wetting deformation with stress level and confining pressure. According to the test results, the wetting deformation of the gravelly soil core materials is obviously related to the stress level and the confining pressure. Under of high confining pressure and stress level, the external force changes the saturation state of a specimen, and the gravel soil sample gradually transits from an unsaturated state to a nearly saturated one, indicating that a 'stress saturation' phenomenon exists in the gravelly soil materials, and resulting in less obvious wetting deformation during the wetting process. When the confining pressure is small, the wetting strain increases with the increasing stress level. When the confining pressure reaches a certain value, the wetting strain decreases with the increasing stress level, presenting an obvious bifurcation phenomenon, showing a more complex pattern. Finally, a wetting deformation model for gravel soil and its parameters are put forward, and can be used as the basis of wetting deformation analysis of high earth-rock dams.
-
-
图 4 砾石土料湿化变形试验时程曲线[6]
Figure 4. Time-history curves of wetting deformation tests on gravelly soil core wall materials
表 1 砾石土心墙料大型三轴CD试验成果表
Table 1 Large-scale triaxial CD test results of gravelly soil core materials
试验干密度/(g·cm-3) 抗剪强度指标 E-μ(B)模型参数 cd/kPa φd/(°) φ0/(°) Δφ/(°) K n Rf G F D Kb m 2.00 65 26.3 34.7 5.8 421 0.34 0.80 0.40 0.12 2.60 172 0.34 2.00 62 26.6 34.0 5.0 458 0.40 0.85 0.35 0.08 3.10 213 0.31 表 2 砾石土心墙料湿化变形量
Table 2 Wetting deformations of gravelly soil core materials
单位:% 围压/MPa SL=0.0 SL=0.2 SL=0.4 SL=0.6 SL=0.8 轴变 体变 Srb 轴变 体变 Srb 轴变 体变 Srb 轴变 体变 Srb 轴变 体变 Srb 0.2 0.419 0.885 75.3 0.890 1.071 76.2 2.000 1.470 78.1 3.509 1.860 79.6 5.729 2.179 80.3 0.4 0.482 0.876 76.7 0.745 1.040 78.1 1.397 1.294 80.0 2.154 1.489 78.9 3.768 1.722 81.0 0.8 0.518 0.935 77.0 0.573 0.793 81.6 0.536 0.815 81.1 0.492 0.467 86.5 0.584 0.318 89.5 1.2 0.412 0.700 81.7 0.324 0.495 84.1 0.178 0.392 88.5 0.203 0.173 88.6 0.058 0.097 94.9 1.6 0.243 0.255 82.7 0.138 0.216 84.2 0.064 0.109 91.2 0.029 0.062 94.7 0.049 0.042 95.1 表 3 砾石土料湿化模型参数
Table 3 Wetting model parameters of gravelly soil core materials
湿化轴向应变 a1 b1 c1 d1 f1 g1 -0.004 0.057 0.337 0.023 -0.858 5.244 湿化体积应变 av bv cv dv fv gv -0.010 0.139 0.659 0.022 -0.684 2.770 -
[1] 余挺. 砾质土防渗料在高土石坝上的应用[J]. 水电站设计, 2003, 19(3): 15-17. https://www.cnki.com.cn/Article/CJFDTOTAL-SDSJ200303004.htm YU Ting. Application of gravelly soil impervious material in high earth-rock dam[J]. Design of Hydroelectric Power Station, 2003, 19(3): 15-17. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SDSJ200303004.htm
[2] 黄玲, 徐晗, 饶锡保, 等. 砾质土钻孔灌砂工艺三轴试验效果研究[J]. 长江科学院院报, 2009, 26(12): 84-88. https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB200912023.htm HUANG Ling, XU Han, RAO Xibao, et al. Triaxial tests effect study on drilling and pumped sands of gravelly soil[J]. Journal of Yangtze River Scientific Research Institute, 2009, 26(12): 84-88. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-CJKB200912023.htm
[3] 朱俊高, 龚选, 周建方, 等. 不同剪切速率下掺砾料大三轴试验[J]. 河海大学学报(自然科学版), 2014, 42(1): 29-34. https://www.cnki.com.cn/Article/CJFDTOTAL-HHDX201401008.htm ZHU Jungao, GONG Xuan, ZHOU Jianfang, et al. Large-sc ale triaxial tests on behavior of gravelly soil at different shearing rates[J]. Journal of Hohai University (Natural Sciences), 2014, 42(1): 29-34. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HHDX201401008.htm
[4] 李玲琳. 狮子坪水电站心墙堆石坝砾石土料施工期大型三轴压缩试验[J]. 四川水力发电, 2013, 32(5): 92-94. https://www.cnki.com.cn/Article/CJFDTOTAL-SCSL201305072.htm LI Linglin. Large-scale triaxial compression test of gravel soil material for core rockfill dam of Shiziping Hydropower Station during construction period[J]. Sichuan Water Power, 2013, 32(5): 92-94. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SCSL201305072.htm
[5] 程展林, 丁红顺, 左永振, 等. 砾石土大型三轴试验砂芯加速排水方法及试样成孔制样器: CN101655424A[P]. 2010-02-24. CHENG Zhan-lin, DING Hong-shun, ZUO Yong-zhen, et al. Accelerated drainage method and sample making device of sand core in large scale triaxial test of gravelly soil CN101655424A[P]. 2010-02-24. (in Chinese)
[6] 左永振, 程展林, 潘家军, 等. 砾石土心墙料的大三轴湿化变形试验与规律分析[J]. 岩土工程学报, 2020, 42(增刊2): 37-42. doi: 10.11779/CJGE2020S2007 ZUO Yongzhen, CHENG Zhanlin, PAN Jiajun, et al. Large-scale triaxial wetting deformation tests and laws of gravelly soil core materials[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(S2): 37-42. (in Chinese) doi: 10.11779/CJGE2020S2007
-
其他相关附件