高填方碎石土地基强夯加固效果及动应力响应规律研究
Study on Dynamic Compaction Reinforcement Effect and Dynamic Stress Response Patterns of High-Fill Gravel Soil Foundation
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摘要: 为研究不同夯击能对高填方碎石土地基加固效果和土动应力的影响, 该文以重庆某动车所地基为研究对象, 通过现场强夯试验研究不同夯击能下地基的夯沉量及动力触探击数, 探讨夯击能对地基加固效果的影响; 通过FLAC3D数值模拟试验研究不同夯击能下地基的内部土体变形和土动应力变化规律, 揭示强夯能量的传递规律。结果表明: 强夯对于土体的加固效果主要在最佳夯击击数之前; 2~3 m深度范围为强加固区, 随着能级的增大, 土动应力峰值和动力触探击数的增大幅度逐渐减小; 高能级在浅层土体范围内的土动应力峰值衰减速度比低能级小, 在多次夯击作用下浅层土体已压密稳定, 冲击能量从浅层向深层传递, 越接近地基表面土动应力变化幅度越小。Abstract: To investigate the effects of different compaction energies on the reinforcement effect and soil dynamic stress of high-fill crushed stone foundations, this paper takes the foundation of a bullet train de-pot in Chongqing as the research object. The field dynamic compaction tests are conducted to analyze the compaction settlement and dynamic penetration blow counts under various compaction energies, and the influence of compaction energy on foundation reinforcement is discussed. The FLAC3D numerical simulations are performed to explore the deformation of internal soil mass and variation patterns of soil dynamic stress under different compaction energies, so as to reveal the transmission patterns of dynamic compaction energy. The results show that the reinforcement effect of dynamic compaction on soil is mainly achieved before the optimal number of tamps. The depth range of 2 to 3 meters is identified as the high reinforced zone. As the compaction energy increases, the growth rates of peak dynamic soil stress and dynamic penetration blow counts gradually decline. The peak soil dynamic stress in shallow soil attenuates lower under high-energy than that under low energy. After multiple compaction, the shallow soil becomes compacted and stable, and the impact energy transfers from shallow to deep layers. The closer to the foundation surface, the smaller the variation amplitude of soil dynamic stress.
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