Experimental Study on Strength and Deformation Characteristics of Red-Bed Soil-Rock Mixture Under Wetting-Drying Cycles
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摘要:
为研究干湿循环下红层土石混合料的劣化规律，以取自四川盆地的红层土石混合料为研究对象，通过静态崩解试验，探讨不同粒径红层软岩块石的崩解特征；对2组红层土石混合路基填料原始级配缩尺，通过叠环式剪切试验，研究干湿循环次数对红层土石混合料黏聚力、内摩擦角、剪胀率和剪切模量等指标的影响. 研究结果表明：红层软岩块石遇水崩解显著，崩解过程可分为剧烈段、过渡段和稳定段，崩解剧烈段块石含量降低近70%；粒径较大时，块石受结构面影响更强，崩解更彻底；随干湿循环次数的增加，抗剪强度在崩解剧烈段明显降低，过渡段基本不变，稳定段略有回升；块石崩解后，其咬合作用显著降低，表观黏聚力急剧减小，静电引力和固化胶结使黏聚力轻微增大，崩解物间的摩擦和重定向排列使内摩擦角轻微增大；最大粒径和含石量显著降低，法向应力下土石混合料更密实，剪胀率明显降低；骨架-密实结构转变为悬浮-密实结构，剪切模量明显降低；干湿循环下黏聚力和剪胀率劣化更明显，内摩擦角的劣化受块石粒径影响最大，剪切模量的劣化受块石粒径影响最小；路堤填筑前，对红层土石混合料进行2次崩解处理，以削弱其受降雨-蒸发循环作用的不利影响.
Abstract:In order to study the deterioration law of the red-bed soil-rock mixture (RB-SRM) under wetting-drying cycles, the RB-SRM in Sichuan Basin was considered as the research object. The disintegration characteristics of red-bed soft rock blocks with different particle sizes were discussed through static disintegration tests. The original gradation scale of two groups of red-bed soil-rock mixed subgrade fillers was studied. The effects of wetting-drying cycle times on the cohesion, internal friction angle, dilation rate, and shear modulus of RB-SRM were studied by the laminated shear test. The results show that the red-bed soft rock block disintegrates significantly in water, and the disintegration process can be divided into the severe stage, transitional stage, and stable stage. The content of the disintegrated rock block in the severe stage is reduced by nearly 70%; for rock block with a larger particle size, it is more affected by the structural plane, and the disintegration is more significant. With the increase in the number of wetting-drying cycles, the shear strength is significantly reduced in the severe stage, while that in the transitional stage is basically unchanged and slightly recovered in the stable stage. After the disintegration of the rock block, the interlocking is significantly reduced; the apparent adhesion is sharply reduced, and the electrostatic attraction and the curing cementation slightly increase the cohesion. The friction and the redirection arrangement among the disintegrated RB-SRM slightly improve the internal friction angle. The maximum particle size and content of rock blocks are significantly reduced so that the RB-SRM is denser, and the dilation rate is significantly reduced under normal stress. Meanwhile, the skeleton-dense structure is transformed into a suspension-dense structure, and the shear modulus is significantly reduced. The degradation of cohesion and dilation rate under wetting-drying cycles is more obvious. The deterioration of the internal friction angle is mostly affected by the particle size of the blocks, and that of the shear modulus is least affected. Before embankment filling, it is suggested to disintegrate the RB-SRM twice to reduce the adverse effect of rainfall-evaporation cycles.
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图 1 红层土石混合料的各粒组土样
Figure 1. Soil samples of each particle group of red-bed soil-rock mixture （RB-SRM）
图 7 干湿循环下崩解物粒组含量变化曲线
Figure 7. Curves of the content of disintegrated RB-SRM with different particle sizes under wetting-drying cycles
图 9 干湿循环下归一化强度劣化曲线
Figure 9. Curves of normalized strength under wetting-drying cycles
图 10 干湿循环下红层土石混合料的强度机理
Figure 10. Strength mechanism of RB-SRM under wetting-drying cycles
图 11 干湿循环下强度指标水平中心梯度分布
Figure 11. Horizontal center gradient distribution of strength parameters under wetting-drying cycles
图 14 干湿循环下归一化力学效应指标分布曲线
Figure 14. Curves of normalized mechanical parameters under wetting-drying cycles
表 1 岩土体基本物理力学指标
Table 1. Basic physical and mechanical parameters of RB-SRM
类型 $\rho $/ （g•cm−3） w/% ${G_{\text{s}}}$ c/kPa φ/（°） ${\sigma _{\text{c}}}$/
MPa黏土 1.78 16.67 2.72 25.32 27.07 粉砂质泥岩 2.56 1.92 560.00 38.40 6.83 
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表 2 干湿循环下红层土石混合料叠环式剪切试验方案
Table 2. Laminated shear test scheme of RB-SRM under wetting-drying cycles
级配 试验组 n/次 法向应力${\sigma _{\text{n}}}$/kPa 级配 Ⅰ 1 0 100，200，400，800 2 1 100，200，400，800 3 2 100，200，400，800 4 4 100，200，400，800 5 6 100，200，400，800 级配 Ⅱ 6 0 100，200，400，800 7 1 100，200，400，800 8 2 100，200，400，800 9 4 100，200，400，800 10 6 100，200，400，800
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表 3 干湿循环下红层土石混合料的力学效应指标
Table 3. Mechanical parameters of RB-SRM under wetting-drying cycles
类型 n/次 c/kPa $\varphi $/（°） $\eta $ ${G_{{\text{0}}{\text{.02}}}}$/MPa 级配Ⅰ 0 94.87 21.24 −0.09 7.78 1 15.17 23.20 −0.15 6.06 2 25.55 20.79 −0.15 5.60 4 26.80 20.97 −0.15 5.29 6 27.17 23.24 −0.15 6.15 级配Ⅱ 0 74.85 30.56 −0.07 9.02 1 63.58 20.04 −0.12 6.75 2 67.53 19.37 −0.09 7.07 4 47.84 22.93 −0.12 6.60 6 51.96 24.01 −0.11 7.13
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[1] 杨宗才,张俊云,周德培. 红层泥岩边坡快速风化特性研究[J]. 岩石力学与工程学报,2006,25(2): 275-283.YANG Zongcai, ZHANG Junyun, ZHOU Depei. Study on fast weathering characteristics of red bed mudstone slope[J]. Chinese Journal of Rock Mechanics and Engineering, 2006, 25(2): 275-283. [2] HE Z L, ZHANG J Y. Compaction quality inspection method of soil-rock filled embankment based on continuous compaction control technology[J]. Advances in Civil Engineering, 2021: 8894042.1-8894042.12. [3] XU W J, XU Q, HU R L. Study on the shear strength of soil-rock mixture by large scale direct shear test[J]. International Journal of Rock Mechanics and Mining Sciences, 2011, 48(8): 1235-1247. doi: 10.1016/j.ijrmms.2011.09.018 [4] 董云,柴贺军. 土石混合料室内大型直剪试验的改进研究[J]. 岩土工程学报,2005,27(11): 1329-1333.DONG Yun, CHAI Hejun. Improvement study of lab large-scale direct shear test of rock-soil aggregate mixture[J]. Chinese Journal of Geotechnical Engineering, 2005, 27(11): 1329-1333. [5] HE Z L, ZHANG J Y, SUN T. Influence of maximum particle diameter on the mechanical behavior of soil-rock mixtures[J]. Advances in Civil Engineering, 2020, 2020: 8850221.1-8850221.9. [6] WEI H Z, XU W J, WEI C F, et al. Influence of water content and shear rate on the mechanical behavior of soil-rock mixtures[J]. Science China Technological Sciences, 2018, 61(8): 1127-1136. doi: 10.1007/s11431-017-9277-5 [7] 郑明新,徐朋威,杨汶明,等. 江西白垩系泥质粉砂岩崩解试验研究[J]. 地下空间与工程学报,2021,17(2): 374-381,429.ZHENG Mingxin, XU Pengwei, YANG Wenming, et al. Experimental study on disintegration of cretaceous argillaceous siltstone in Jiangxi province[J]. Chinese Journal of Underground Space and Engineering, 2021, 17(2): 374-381,429. [8] 周翠英,谭祥韶,邓毅梅,等. 特殊软岩软化的微观机制研究[J]. 岩石力学与工程学报,2005,24(3): 394-400.ZHOU Cuiying, TAN Xiangshao, DENG Yimei, et al. Research on softening micro-mechanism of special soft rocks[J]. Chinese Journal of Rock Mechanics and Engineering, 2005, 24(3): 394-400. [9] 吴道祥,刘宏杰,王国强. 红层软岩崩解性室内试验研究[J]. 岩石力学与工程学报,2010,29(增2): 4173-4179.WU Daoxiang, LIU Hongjie, WANG Guoqiang. Laboratory experimental study of slaking characteristics of red-bed soft rock[J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29(S2): 4173-4179. [10] 慕焕东,邓亚虹,李荣建. 干湿循环对地裂缝带黄土抗剪强度影响研究[J]. 工程地质学报,2018,26(5): 1131-1138.MU Huandong, DENG Yahong, LI Rongjian. Experimental study on strength characteristics of loess at ground fissures in Xi’an under action of dry and wet cycle[J]. Journal of Engineering geology, 2018, 26(5): 1131-1138. [11] 万勇,薛强,吴彦,等. 干湿循环作用下压实黏土力学特性与微观机制研究[J]. 岩土力学,2015,36(10): 2815-2824.WAN Yong, XUE Qiang, WU Yan, et al. Mechanical properties and micromechanisms of compacted clay during drying-wetting cycles[J]. Rock and Soil Mechanics, 2015, 36(10): 2815-2824. [12] 曾铃,罗锦涛,侯鹏,等. 干湿循环作用下预崩解炭质泥岩裂隙发育规律及强度特性[J]. 中国公路学报,2020,33(9): 1-11.ZENG Ling, LUO Jintao, HOU Peng, et al. Crack development and strength characteristics of pre-disintegrated carbonaceous mudstone under dry-wet cycles[J]. China Journal of Highway and Transport, 2020, 33(9): 1-11. [13] 唐朝生,施斌. 干湿循环过程中膨胀土的胀缩变形特征[J]. 岩土工程学报,2011,33(9): 1376-1384.TANG Chaosheng, SHI Bin. Swelling and shrinkage behavior of expansive soil during wetting-drying cycles[J]. Chinese Journal of Geotechnical Engineering, 2011, 33(9): 1376-1384. [14] TABIBNEJAD A, HESHMATI A, SALEHZADEH H, et al. Effect of gradation curve and dry density on collapse deformation behavior of a rockfill material[J]. KSCE Journal of Civil Engineering, 2015, 19(3): 631-640. doi: 10.1007/s12205-013-0682-5 [15] LI S Q, YAGN Z P, TAIN X, et al. Influencing factors of scale effects in large-scale direct shear tests of soil-rock mixtures based on particle breakage[J]. Transportation Geotechnics, 2021, 31: 100677.1-100677.12. [16] LADE P V. Assessment of test data for selection of 3-D failure criterion for sand[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2006, 30(4): 307-333. doi: 10.1002/nag.471 [17] 刘新荣,涂义亮,王鹏,等. 基于大型直剪试验的土石混合体颗粒破碎特征研究[J]. 岩土工程学报,2017,39(8): 1425-1434.LIU Xinrong, TU Yiliang, WANG Peng, et al. Particle breakage of soil-rock aggregate based on large-scale direct shear tests[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(8): 1425-1434. [18] 杨忠平,李进,蒋源文,等. 含石率对土石混合体-基岩界面剪切力学特性的影响[J]. 岩土工程学报,2021,43(8): 1443-1452.YANG Zhongping, LI Jin, JIANG Yuanwen, et al. Influences of stone content on shear mechanical properties of soil-rock mixture-bedrock interface[J]. Chinese Journal of Geotechnical Engineering, 2021, 43(8): 1443-1452. [19] POTYONDY D O, CUNDALL P A. A bonded-particle model for rock[J]. International Journal of Rock Mechanics and Mining Sciences, 2004, 41(8): 1329-1364. doi: 10.1016/j.ijrmms.2004.09.011 [20] XU W J, HU L M, GAO W. Random generation of the meso-structure of a soil-rock mixture and its application in the study of the mechanical behavior in a landslide dam[J]. International Journal of Rock Mechanics and Mining Science, 2016, 86: 166-178. doi: 10.1016/j.ijrmms.2016.04.007 [21] 朱顺然,徐超,丁金华. 土工织物-砂土界面的叠环式剪切试验[J]. 岩土力学,2018,39(5): 1775-1780,1788.ZHU Shunran, XU Chao, DING Jinhua. Laminated shear test of geotextile-sand interface[J]. Rock and Soil Mechanics, 2018, 39(5): 1775-1780,1788. [22] 江洎洧,程展林,潘家军,等. 基于大型叠环剪切试验的松散土石体强度及变形特性试验研究[J]. 岩石力学与工程学报,2017,36(增1): 3636-3643.JIANG Jiwei, CHENG Zhanlin, PAN Jiajun, et al. Experimental study on the stress-strain and strength characteristics of loose rock-soil aggregates based on large-size stacked ring shear test[J]. Chinese Journal of Rock Mechanics and Engineering, 2017, 36(S1): 3636-3643. [23] 中华人民共和国住房和城乡建设部. 土工试验方法标准: GB/T 50123—2019[S]. 北京: 中国计划出版社, 2019. [24] 刘晓明,颜圣,刘凯,等. 干湿循环作用下红层软岩填料强度特性试验研究[J]. 公路交通科技,2020,37(3): 24-30.LIU Xiaoming, YAN Sheng, LIU Kai, et al. Experimental study on strength properties of red bed weak rock filler under dry-wet cycles[J]. Journal of Highway and Transportation Research and Development, 2020, 37(3): 24-30. [25] KISHIDA H, UESUGI M. Tests of the interface between sand and steel in the simple shear apparatus[J]. Géotechnique, 1987, 37(1): 45-52. [26] 魏厚振,汪稔,胡明鉴,等. 蒋家沟砾石土不同粗粒含量直剪强度特征[J]. 岩土力学,2008,29(1): 48-51,57.WEI Houzhen, WANG Ren, HU Mingjian, et al. Strength behaviour of gravelly soil with different coarse-grained contents in Jiangjiagou ravine[J]. Rock and Soil Mechanics, 2008, 29(1): 48-51,57. [27] 徐文杰,胡瑞林,曾如意. 水下土石混合体的原位大型水平推剪试验研究[J]. 岩土工程学报,2006,28(7): 814-818.XU Wenjie, HU Ruilin, ZENG Ruyi. Research on horizontal push-shear in situ test of subwater soil-rock mixture[J]. Chinese Journal of Geotechnical Engineering, 2006, 28(7): 814-818. -
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