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通过横琴海底专用隧道工程,研究了滨海饱和淤泥土中模袋围堰工程的设计方法和施工关键技术,分析了模袋围堰在隧道工程施工过程中的变形规律。随着围堰内侧水位逐渐下降,堰底下土中超孔隙水压力逐步消散,且工后初期消散较快,随后逐渐减小。填砂加载和围堰内侧降水对堰底下土层压缩变形规律,以及土中超孔隙水压力变化规律的影响随深度的增加逐渐减小,且影响深度约为2倍围堰高度。围堰加载过程中和施工完成初期,围堰沉降主要由模袋砂压缩和堰底下土层主固结压缩组成,且沉降速率较快;此后随着堰底下土层中超孔隙水压力的逐步消散,以及砂土模袋压缩变形趋于稳定,围堰沉降主要为堰底下分层土的次固结压缩变形,且沉降速率逐渐减小,在外界环境不变的条件下,趋向收敛。
Through the Hengqin submarine special tunnel project, the design method and key construction technology of the mold bag cofferdam in the coastal saturated silt are studied, and the deformation rules of the mold bag cofferdam in the tunnel construction are analyzed. With the gradual decrease of the water level inside the cofferdam, the excess pore water pressure in the soil below the weir gradually dissipated and dissipated rapidly in the early post-industrial period and then gradually decreased. The effect of sand loading and internal cofferdam precipitation on compressive deformation of soil under the weir and the variation law of excess pore water pressure in soil decreases with the increase of depth, and the influence depth is about 2 times the height of cofferdam. During cofferdam loading and early completion of construction, cofferdam settlement is mainly composed of compression of bag sand and main consolidation compression of soil under the weirs, and the settlement rate is relatively rapid. Since then, as the excess pore water pressure in the soil under the weir gradually dissipates , And the compression deformation of sand mold bag tends to be stable. The cofferdam settlement is mainly sub-consolidation compression deformation of subsoil stratified soil, and the sedimentation rate decreases gradually, and tends to converge under the condition of constant external environment.