Experimental study on the dynamic response of aeolian sand subgrade reinforced by geocells at different depths
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摘要:
风积沙路基的处理一直是沙漠公路建设面临的难题, 土工格室加固方法可为沙漠公路建设提供一条新路径, 结合S21线(乌鲁木齐-阿勒泰)沙漠公路路基现场试验, 研究不同路基深度动力响应特征, 对土工格室加固风积沙性能探究具有重要的价值及意义。结果表明: ①测试车速对路基不同深度处动应力、动加速度和动速度的时程曲线波动性影响较大, 且提高车速时, 动速度峰值、动加速度峰值和动应力峰值都出现了明显的增加; ②随着路基层深度的不断增加, 动速度幅值、动加速度幅值和动应力幅值均呈现出逐渐衰减的趋势, 其中在土工格室加固风积沙层衰减幅度最大; ③沿路基横断面水平方向上, 动速度幅值、动加速度幅值和动应力幅值均呈指数型衰减的趋势, 距振动源水平距离为5 m时, 其幅值衰减至10%左右, 可将此水平范围作为工程设计参考值。
Abstract:The treatment of aeolian sand subgrade has always been a difficult problem for desert highway construction.The geocell reinforcement method can provide a new path for desert highway construction. Combining the S21 line (Urumqi-Altay) desert highway subgrade field test, it is of great value and significance to study the dynamic response characteristics of different subgrade depths for the study of aeolian sand performance of geocelling reinforcement.The results show that ① The test speed has a great influence on the time-history curve fluctuation of dynamic stress, dynamic acceleration and dynamic velocity at different depths of the subgrade, and the peak values of dynamic velocity, dynamic acceleration and dynamic stress increase obviously with increasing speed. ②With the increase in the road base depth, the amplitudes of the dynamic velocity, dynamic acceleration and dynamic stress show a trend of gradual attenuation, among which the attenuation amplitude is the largest in the geocell-reinforced aeolian sand layer. ③ Along the horizontal direction of the cross section of the subgrade, the amplitude of the dynamic velocity, the amplitude of the dynamic acceleration and the amplitude of the dynamic stress attenuate exponentially. When the horizontal distance from the vibration source is 5 m, the amplitude attenuates to approximately 10%. This horizontal range can be used as a reference value for engineering design.
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Key words:
- desert highway /
- geocell /
- aeolian sand subgrade /
- dynamic response /
- field experiment /
- reinforcement mechanism
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表 1 路基填料的物理性质指标
Table 1. Physical property index of subgrade filling
路基填料 重度/(kN·m-3) 土粒相对密度Gs 含水率/% 不均匀系数Cu 曲线系数Cc 风积沙 16.4 2.55 1.31 2.21 1.06 级配砾石 22.0 2.59 5.70 62.34 1.56 -
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