砂层压密加固效应室内试验研究

张连震; 李志鹏; 张庆松; 俞然刚; 冯慧君

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铁道工程学报 ›› 2020, Vol. 37 ›› Issue (3) : 89-94.

城市轨道工程

砂层压密加固效应室内试验研究

张连震^1**, 李志鹏², 张庆松³, 俞然刚¹, 冯慧君⁴

作者信息 +

Laboratory Test on the Reinforcement Effect of Compaction on Sand

ZHANG Lianzhen¹, LI Zhipeng², ZHANG Qingsong³, YU Rangang¹, FENG Huijun⁴

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文章历史 +

摘要

研究目的: 在隧道工程砂层劈裂注浆或压密注浆工程中都伴随着砂层的压密现象,被压密砂层性能的提升幅度对于注浆加固体的整体性能具有显著影响。基于此,以黏聚力、内摩擦角、渗透系数作为表征砂层压密加固效应的性能指标,以青岛地区含黏性土砂层为典型砂层介质,测试不同黏性土含量条件下砂层性能随压密程度的增长情况,获得砂层各项性能指标与所受压力的定量关系,在此基础上分析黏性土含量对被压密砂层性能提升幅度的影响,提出以临界黏性土含量为指标的砂层压密加固有效性评价标准。
研究结论: (1)注浆压密作用可显著提升砂层的各项性能指标,在室内试验条件下,砂层黏聚力增长了30.8~87.6 kPa,内摩擦角提高了13°~15°,渗透系数降低了2~5个数量级;(2)被压密砂层性能提升幅度与黏性土含量正相关,当砂层黏性土含量小于临界黏性土含量时,砂层无法通过压密手段进行有效加固;(3)该研究结果可应用于隧道工程穿越砂层注浆加固领域,对注浆设计有一定借鉴作用。

Abstract

Research purposes: For fracture grouting mode or compaction grouting mode in sand layer, compaction behavior of sand occurs currently. Improvement degree of performance of compacted sand has a marked effect on macroscopical performance of grouted body. Cohesive strength, internal friction angle and permeability coefficient are used as performance indexes of compaction reinforcing effect. With clayey sand layer in Qingdao district as the typical medium, the growth of sand properties with compaction degree under different clay contents was tested, and the quantitative relationship between compaction reinforcing effect and grouting pressure was acquired. At the same time, the effect of clay content on the performance improvement of compacted sand layer was analyzed. Finally, the evaluation index was put forward to evaluate whether sand layer can be effectively reinforced by compaction method, which was characterized by critical clay content.
Research conclusions: (1) Grouting compaction can significantly improve various performance indexes of sand layer. Under laboratory test condition, cohesive strength has risen by 30.8~87.6 kPa, internal friction angle has risen by 13~15°, and permeability coefficient has decreased by 2~5 order of magnitude. (2) The performance improvement of the compacted sand layer is positively correlated with clay content. When clay content less than critical clay content, sand layer can not be effectively reinforced by compaction method. (3) The research results can be applied to the field of grouting reinforcement in tunnel engineering through sand layer, and can be used to guide grouting design.

导出引用

张连震, 李志鹏, 张庆松, 等. 砂层压密加固效应室内试验研究[J]. 铁道工程学报, 2020, 37(3): 89-94

ZHANG Lianzhen, LI Zhipeng, ZHANG Qingsong, et al. Laboratory Test on the Reinforcement Effect of Compaction on Sand[J]. Journal of Railway Engineering Society, 2020, 37(3): 89-94

中图分类号： TU45

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