波浪和潮波作用下临海深基坑渗流特性研究

In recent years, with the development of the economy in China, a large number of deep excavations have been executed under hydrodynamic environment during the construction of high-rise buildings, underground space by seas or rivers, sea-crossing tunnel, sea-crossing bridge and other large scale projects. The safety of such engineering is of great importance and the impact of construction on the surrounding environment must be focused on. During which the seepage characteristics and its failure control of deep excavations under the cyclic wave and tide wave are the key scientific issues to be addressed..This project will present a seepage analysis model of deep excavations by seas and rivers. On the basis of the wave flume model tests, the corresponding nonlinear numerical analysis methods as well as analytic theory, the seepage characteristics and its failure mechanism of excavation under cyclic wave and wave tidal will be studied. The research work will reveal the pore pressures response around the excavation subjected to cyclic wave and wave tidal loading, the earth pressures and pore pressures distribution on the retaining structures, as well as the failure model. The analysis and design methods of the internal forces, the deformation, and the stability of the retaining structures will be presented. The project will develop the analysis and design theories of the excavation under complex environments remarkably, and also provides the necessary scientific technical support for the design of excavation schemes by the sea or by the river, which will have important significance.

近年来随着我国经济的发展，在临海或临江地区高层建筑、地下空间开发，跨海（江）隧道、跨海大桥等重大工程的建设过程中，涌现了大量紧临动水环境施工的深基坑工程，这类工程的安全和施工对周围环境的影响问题十分突出，其中在波浪、潮波循环作用下的深基坑渗流特性及破坏控制是需解决的关键科学问题。.本项目从临海深基坑渗流机理出发，根据相应的波浪水槽模型试验、非线性数值分析方法和解析理论，建立波浪、潮波作用下基坑的渗流分析模型，在此基础上开展波浪、潮波循环作用下基坑渗流的模型试验、数值分析与解析研究，深入揭示波浪、潮波循环作用下基坑周围的孔压响应和支护结构水土压力变化及渗流破坏机理，并提出相应的基坑支护结构内力、变形和稳定的分析和设计方法。无疑将极大地丰富和发展复杂环境下深基坑支护结构的设计计算理论，为临海、临江深基坑支护结构设计提供必要的科学依据，具有重要的科学意义和应用价值。

近年来随着我国经济的发展，在临海或临江地区高层建筑、地下空间开发，跨海（江）隧道、跨海大桥等重大工程的建设过程中，涌现了大量紧临动水环境施工的深基坑工程，这类工程的安全和施工对周围环境的影响问题十分突出，其中在波浪、潮波循环作用下的深基坑渗流特性及破坏控制是需解决的关键科学问题。. 本项目研制了适合波浪水槽内开展试验的基坑渗流试验模型箱，开展了一系列波浪作用下临海粘质粉土基坑周围的孔压响应规律的模型试验研究；研制了潮汐作用下基坑渗流的室内试验模型装置，开展了潮汐作用下临海粘质粉土基坑的孔压响应规律和基坑的渗流规律及渗流破坏试验研究。建立了滨海基坑浅层含水层地下水位波动和临海基坑水位波动两种情况下的基坑渗流分析模型，开展了动水作用下基坑及周围地基的水土压力响应的有限元数值分析。推导了滨海地区基坑坑外地下水位波动引起土体超静孔压响应的简化一维解析解；获得了水位波动情况下基坑周围地基孔压响应的二维近似半解析解。研究发现由潮汐水位波动引起的基坑周围地基的相对超孔压波动幅值沿坑外到坑内的最短渗流路径逐渐衰减，坑外地下水位波动时基坑周围孔压波动滞后现象明显；经受波浪作用的临海基坑若忽视土体超孔压累积效应将偏不安全。. 项目深入揭示了波浪、潮波作用下基坑周围的孔压响应和支护结构水土压力变化及渗流破坏机理，丰富和发展了复杂环境下深基坑支护结构的设计计算理论，为临海、临江深基坑支护结构设计提供必要的科学依据，具有较强的科学意义和应用价值。