海底隧道复合注浆技术及其工程应用

针对海底隧道不良地质体注浆加固必须同时满足稳定性、致密性和承受高水压作用的特殊要求,提出复合注浆新理念,即通过材料复合和工艺复合在围岩中形成功能型复合结构以实现安全控制和高效堵水。为此,首先建立浆液扩散机制模型,揭示注浆范围与浆脉厚度等空间分布特性及其影响因素;创建复合加固体的壳体力学模型,可对加固体的稳定性进行预测及评价,进而提出宏观力学参数的确定方法;系统分析加固体力学性能的主要影响因素,提出注浆参数的设计方法,由此可对复合注浆实现全过程工艺控制;基于复合注浆体功能型结构特点,创造隧道周边帷幕注浆技术,并首次提出采用堵水率、加固体强度和整体稳定性作为注浆效果的评价指标,较日本青函隧道等采用的全断面注浆方式显著提高了效率和可靠性。最后介绍复合注浆技术在厦门翔安海底隧道F1风化槽强透水地段的应用,达到了预期效果,确保了工程安全,由此形成了海底隧道穿越不良地质体的地层加固技术模式。

Composite grouting technology for subsea tunnels and its engineering application

In order to meet the special requirements of stability,compactness and capacity of high water pressure,a new concept of composite grouting,adopting composite material and process to form a functional composite structure and further to realize the dual effect of safety control and efficient water plugging,was proposed. A diffusion model of slurry vein was established,and the spatial distribution characteristics of the grouting range and the thickness of slurry vein and the influencing factors were revealed. A mechanical model of slurry vein skeleton and composite shell for evaluating the stability of the grouted region was established,and a determining method of macro-mechanical parameters was proposed. The main influencing factors of mechanical properties of the grouted region were analyzed,and a design method of grouting parameters was put forward. As a result,the whole process control of composite grouting can be realized. Based on the feature of composite grouting body functional structure,a technology of peripheral curtain grouting of tunnels was developed,and the water plugging rate,grouting region strength and overall stability were proposed as the evaluation indices of grouting effect. Compared with the full-sectional grouting method,the efficiency and reliability of the developed technology are significantly improved. Finally,the application of the composite grouting technique in the highly permeable area of F1 weathering trough of Xiang'an subsea tunnel in Xiamen was introduced,and it is shown that,by using the technology,the expected effect is achieved and the engineering safety is ensured.