深厚超软土地基增压式真空预压加固机理及关键技术研究

The shortage of land resources and the problem of ecological environment have become the main bottleneck restricting the sustainable development of China's economy and a major hidden danger affecting the national strategic security. The deformation control theory and reinforcement failure of deeply ultra-soft soil foundation in coastal area are studied in regarding to its undesirable engineering characteristics from newly reclamation. The project is willing to study by using laboratory macro and micro tests, model tests, COMSOL Multiphysics numerical simulations, Particle Flow Code and theoretical analysis. The aim of this project is to explore the difference between reclaimed ultra-soft soil and soft soil; To reveal the microscopic behaviors and the characteristics of soil particles migration and the formation mechanism of clogging during vacuum preloading; To evaluate the mechanism of migration and clogging of vacuum preloaded particles quantitatively, and then the effect of gas injection pressure on the macroscopic and microscopic mechanical properties of soil particles; To establish a foundation settlement prediction model based on the micro-mechanism and macro-characteristics of deeply ultra-soft soil, for evaluating the deformation evolution law quantitatively. The research results could be applied to the long-term safety of constructions on deeply ultra-soft foundations in coastal area directly, which plays an important role in supporting the construction of high efficiency, environmental and green geotechnical engineering, and has great academic significance and social value as well.

陆域资源匮乏和生态环境问题已成为制约我国经济可持续发展的主要瓶颈和影响国家战略安全的重大隐患。围绕新型吹填造陆形成的深厚超软土地基诸多不良工程特性，进行深厚超软土地基变形控制和加固失效等科学问题及增压式真空预压加固机理和关键技术研究。综合运用室内宏微观试验、模型试验、理论分析，结合多物理场建模与仿真数值分析和颗粒流计算程序，探索吹填超软土与正常沉积软土差异性，揭示真空预压过程中土体颗粒迁移微观行为和表征特性规律及淤堵泥层形成机理；定量评价增压式真空预压颗粒运移和阻塞改变机理及增压压力对孔隙介质颗粒宏微观力学特性影响；建立基于深厚超软土微观机制及宏观特性的地基沉降预测模型，定量评价其变形演化规律。研究成果可直接应用于沿海地区深厚超软土地基及其上部建（构）筑物的长期安全建设和使用，对高效环保绿色岩土工程建设起到重要支撑作用，具有重大学术意义和社会价值。

陆域资源匮乏和生态环境问题是制约我国经济可持续发展的主要瓶颈和影响国家战略安全的重大隐患。围绕新型吹填造陆形成的深厚超软土地基工程问题频发、上部建（构）筑物不同程度破坏，社会与经济损失巨大等严峻问题，项目完成了深厚超软土地基变形控制和加固失效淤堵泥层形成机制及增压式真空预压加固机理和关键技术研究。.根据执行计划，运用室内静、动三轴试验和SEM电镜扫描及压汞微观测试、吹填土和人工配置透明土模型试验、固结理论分析方法，结合多物理场建模与仿真数值分析，探索得到了吹填超软土与正常沉积软土宏微观差异性，揭示出真空预压过程中土体颗粒迁移微观行为和表征特性规律；分析得到了真空预压加固过程中淤堵泥层形成特性机理及淤堵泥层三阶段发展特征；提出了增压式真空预压加固吹填超软土地基过程中注入气体受孔隙水压力竖向作用上升发展运移机制；依据增压压力对孔隙介质颗粒宏微观力学改变特征，分析得到了增压式真空预压加固超软土地基过程中土体颗粒运移和阻塞改变技术方法；以实际工程建设为依托，针对传统真空预压加固技术存在能耗高、排水板易淤堵、工后沉降大、加固效果欠佳等一系列工程问题，计算分析得到适用于深厚吹填超软土地基的增压式真空预压技术参数。.项目完成了研究计划并取得了预期成果，录用发表SCI/EI论文6篇，授权发明专利1项，授权实用新型专利1项；指导3名硕士研究生已形成硕士学位论文。研究成果已成功应用于沿海地区深厚超软土地基工程建设，对高效环保绿色岩土工程建设起到了理论支撑作用。