Experimental Study on Freeze-thaw Cycle of Collapsible Loess Red Sandstone Integrated Cement Soil Filling Material
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摘要: 在湿陷性黄土地区,基槽回填区常因回填土自身沉降和湿陷等问题产生区域大面积沉降,对建筑正常使用和居民正常生活造成了严重影响。根据区域工程实际,提出湿陷性黄土–红砂岩集成水泥土填筑材料,并通过设置湿陷性黄土、红砂岩、水泥及水的不同占比进行正交试验,得到了利用黄土、红砂岩开发新型基槽回填材料的最佳配合比。通过对集成水泥土试件与素水泥土试件进行冻融循环试验,发现集成水泥土的抗冻性能明显优于素水泥土,具有更好的力学性能与使用耐久性。本研究为湿陷性黄土地区填筑材料的工程应用提供了一定的参考。
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关键词:
- 湿陷性黄土–红砂岩集成水泥土填筑材料 /
- 正交试验 /
- 耐久性能 /
- 冻融循环试验
Abstract: In the collapsible loess area, the backfill area of the foundation trough often produces a large area of settlement due to the self-subsidence and collapsibility of backfill, which has a severe impact on the regular use of buildings and the everyday life of residents. According to the regional engineering practice, the collapsible loess-red sandstone integrated cement-soil filling material is put forward. The orthogonal test was carried out by setting different proportions of collapsible loess, red sandstone, cement, and water. The best mixture ratio of developing new foundation trench backfill material using loess and red sandstone was obtained. Through freeze-thaw cycling tests on integrated cement-soil specimens and plain cement-soil specimens, it was found that the freeze-thaw resistance of integrated cement-soil specimens is significantly better than that of plain cement-soil specimens, with better mechanical properties and durability. This study provides some reference for the engineering application of fill materials in collapsible loess areas. -
表 1 正交试验因素水平表
水平 因素 湿陷性黄土与红砂岩比例 水泥掺量/% 用水量/% 1 60:40 6 8 2 65:35 8 10 3 70:30 11 15 4 75:25 13 20 5 80:20 15 25 表 2 正交试验结果
试验号 湿陷性黄土和
红砂岩比例水泥用量/% 用水量/% 无侧限抗压
强度/MPa1 60∶40 6 8 1.320 2 60∶40 8 10 1.454 3 60∶40 11 15 1.920 4 60∶40 13 20 2.211 5 60∶40 15 25 2.373 6 65∶35 6 10 1.472 7 65∶35 8 15 1.669 8 65∶35 11 20 1.870 9 65∶35 13 25 2.091 10 65∶35 15 8 2.430 11 70∶30 6 15 1.072 12 70∶30 8 20 1.102 13 70∶30 11 25 2.386 14 70∶30 13 8 2.383 15 70∶30 15 10 3.428 16 75∶25 6 20 1.355 17 75∶25 8 25 1.539 18 75∶25 11 8 1.598 19 75∶25 13 10 3.030 20 75∶25 15 15 3.408 21 80∶20 6 25 1.104 22 80∶20 8 8 1.402 23 80∶20 11 10 2.512 24 80∶20 13 15 2.230 25 80∶20 15 20 2.108 注:湿陷性黄土和红砂岩用量比例均为土体干燥时的质量比,水泥掺量为干燥粗细集料总用量的百分比;用水量为干燥集料与水泥总质量的百分比,因土体具有一定天然含水量,为保持一致,用水量包括土体的天然含水量。 表 3 正交试验极差分析表
K值 湿陷性黄土与红砂岩比例 水泥用量/% 用水量/% K1 9.278 6.323 8.187 K2 9.532 7.166 8.323 K3 10.371 10.286 9.586 K4 10.9 11.945 10.879 K5 9.356 13.737 10.292 k1 1.8556 1.2646 1.6374 k2 1.9064 1.4332 1.6646 k3 2.0742 2.0572 1.9172 k4 2.186 2.3890 2.1758 k5 1.8712 2.7494 2.0584 R 0.3304 1.4848 0.5384 表 4 方差分析结果表
因素 偏差平
方和自由度 平均偏差平方和 F值 显著性 A 0.289 4 0.072 2.182 B 7.824 4 1.956 59.273 显著 C 2.614 4 0.654 19.812 显著 误差 0.133 4 0.033 总和 10.860 20 表 5 湿陷性黄土–红砂岩集成水泥土填筑材料最优配合比
湿陷性黄土与红砂岩的比例 水泥掺量/% 用水量/% 75∶25 15 20 -
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