Assessment of weathering degree and road performance test of weathered rock as subgrade filling
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摘要: 选取了4种代表性风化岩, 分析了其级配组成、击实参数与破碎特性, 研究了风化岩路基长期稳定性的影响因素。开发了能够模拟路基填料自然风化的水温循环试验方法, 研究了风化程度对风化岩填料加州承载比和水温敏感性的影响与水温循环效应对风化岩性质的影响。采用物理风化与化学风化相结合的评价方法, 提出以风化特征指数作为风化程度的评价指标, 分析了风化特征指数与各项路用性能的相关性, 并建立了基于各项路用性能的风化程度分级标准。分析结果表明: 随着风化程度的加大, 风化岩力学性能与水温敏感性降低; 应用水温循环模拟试验能够判别风化岩的长期路用性能; 风化特征指数与风化岩路用性能决定系数大于0.85, 相关性良好, 可用来判定风化岩的风化程度与路用性能; 选用风化特征指数为0.78的风化岩铺筑试验路, 经18个月观测的路基最大沉降为7.8cm, 路用性能良好。Abstract: Four kinds of typical weathered rocks were selected.Their gradation compositions, compaction parameters and fragmentation properties were analyzed.The affecting factors of longterm stability of weathered rock were researched.Water-temperature cycle test method was developed to simulate the natural weathering of subgrade filling.The influence of weathering degree on CBR (California bearing ratio) and water-temperature sensitivity and the influence of water-temperature cycle effect on the properties of weathered rock were researched.Combining physical and chemical weathering evaluation methods, weathering characteristic index was proposed to evaluate the weathering degree.The correlations between weathering characteristic index and road performances of weathered rock were analyzed.The grading standard of the weathering degrees based on the road performances was established.Analysis result shows that when the weathering degree increases, the mechanics performances and water-temperature sensitivity of weathered rock reduce.The long-term road performances of weathered rock can be distinguished by using water-temperature cycle test method.The determination coefficients between weathering characteristic index and road performances are greater than 0.85, so theircorrelations are good, and the index is available to judge the weathering degree and road performances of weathered rock.When the weathering characteristic index is 0.78, after 18 months, the maximum settlement of test road with weathered rock subgrade is 7.8 cm, so its road performances are well.
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图 9 风化岩A水温循环次数与质量损失关系
Figure 9. Relationships between water-temperature cycle times and mass losses for weathered rock A
图 10 风化岩B水温循环次数与质量损失关系
Figure 10. Relationships between water-temperature cycle times and mass losses for weathered rock B
图 11 风化岩C水温循环次数与质量损失关系
Figure 11. Relationships between water-temperature cycle times and mass losses for weathered rock C
图 12 风化岩D水温循环次数与质量损失关系
Figure 12. Relationships between water-temperature cycle times and mass losses for weathered rock D
图 13 水温循环次数与风化岩质量的关系
Figure 13. Relationships between water-temperature cycle times and masses of weathered rocks
图 14 模拟风化前、后CBR结构体膨胀率
Figure 14. CBR expansive rates before and after weathering simulation
图 15 模拟风化前、后风化岩A的贯入试验结果
Figure 15. Penetration test results of weathered rock A before and after weathering simulation
图 16 模拟风化前、后风化岩B的贯入试验结果
Figure 16. Penetration test results of weathered rock B before and after weathering simulation
图 17 模拟风化前、后风化岩C的贯入试验结果
Figure 17. Penetration test results of weathered rock C before and after weathering simulation
图 18 模拟风化前、后风化岩D的贯入试验结果
Figure 18. Penetration test results of weathered rock D before and after weathering simulation
图 24 风化岩路基累计观测沉降
Figure 24. Accumulated observation settlements of weathered rock subgrade
表 4 风化岩水温循环崩解率和质量损失率
Table 4. Disintegration rates and mass loss rates of weathered rocks after water-temperature cycle
下载: 导出CSV
表 5 模拟风化前、后风化岩CBR值
Table 5. CBR values of weathered rocks before and after weathering simulation
下载: 导出CSV
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