| 软基真空预压加固的注气增效机制与数值分析 |
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| 引用本文： | 屠红珍,徐衍徽,谢立全.软基真空预压加固的注气增效机制与数值分析[J].岩土力学,2014,35(Z2):600-606. |
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| 作者姓名： | 屠红珍 徐衍徽 谢立全 |
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| 作者单位： | 1. 温州市港航管理局，浙江 温州 325088；2. 同济大学 土木工程学院，上海 200092 |
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| 基金项目： | 国家自然科学基金（No. 11172213）；中央高校基本科研业务费专项资金资助项目（基础研究人才培养计划20123106）。 |
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| 摘 要： | 无砂垫层真空预压技术已成功应用于软土地基加固工程,但软土的低透水性致使其工期很长。为此提出联合间歇性注气以改进真空预压技术,提高其排水速率、缩短工期。建立联合注气的真空预压法有限元分析模型,通过注气位置与注气压力的改变,对比分析注气前后土体中渗流速度、排水速率、渗透比降等的变化规律。结果表明,注气能显著提高真空预压法的排水速率,增强真空预压法的加固效果;由于气体的轻质特性,在排水板下方注气更有利于排水效果;在不冲破土层的情况下,注气压力越大,促进加固的效果越好。联合注气能有效增强真空预压加固软土地基的排水效率,有着较好的工程应用前景。
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| 关 键 词： | 真空预压 工期 间歇性注气 软基处理 |
| 收稿时间： | 2014-05-15 |
Mechanism and numerical analysis of effect of air injection on vacuum preloading for weak foundation improvement |
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| TU Hong-zhen,XU Yan-hui,XIE Li-quan.Mechanism and numerical analysis of effect of air injection on vacuum preloading for weak foundation improvement[J].Rock and Soil Mechanics,2014,35(Z2):600-606. |
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| Authors: | TU Hong-zhen XU Yan-hui XIE Li-quan |
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| Institution: | 1. Port and Shipping Management Bureau of Wenzhou, Wenzhou, Zhejiang 325088, China; 2. College of Civil Engineering, Tongji University, Shanghai 200092, China |
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| Abstract: | Vacuum preloading technique without sand cushion layer has been successfully applied to the weak foundation reinforcement; but it is difficult to shorten construction period due to the low permeability of weak soil. Intermittent air injection is proposed to increase the drainage rate for vacuum drainage. The combined method of vacuum preloading and air injection is investigated for different conditions of the injecting positions and air pressures based on finite element simulation. Seepage velocity, drainage rate and seepage gradient are compared and analyzed before and after air injection. The simulation results show that the air injection can improve the efficiency of vacuum drainage, so as to enhance the foundation reinforcement and reduce preloading time of the vacuum loading. The efficiency of injecting air below the drain boards is better than that above the bottom ends of boards. And in the case of not breaking through the foundation in the air injection, the greater the air pressure is set, the better effect of reinforcement will be. The combined method of vacuum preloading and air injection could be widely used in the improvement practice of weak ground. |
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| Keywords: | vacuum preloading construction period intermittent air injection weak foundation improvement |
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