堆石混凝土坝面层与坝体采用自密实混凝土(SCC)进行一体化施工可以减少模板用量、提高效率。为探究一体化浇筑过程中柔性网对面层SCC向坝体内流动的阻碍效果,开展了典型坝段的一体化浇筑缩尺模型试验,设计5种不同孔径柔性网,利用空心铁球模拟堆石,研究柔性网阻隔下模型SCC在堆石空隙中的流动距离、堆积高度与入渗坝体体积的变化规律。结果表明:柔性网孔径对模型SCC流动的阻隔效果随着孔径增大而逐渐减弱。柔性网孔径由3 mm增大至8 mm,模型SCC流入坝体内部的距离从88.56 mm增长至273.98 mm,堆积厚度由88.81 mm增至155.21 mm,渗入坝体的体积从65.4 cm³增加至346.0 cm³。选用孔径等于骨料最大粒径的柔性网,可以更有效地限制SCC的流动性;而当柔性网孔径超过骨料最大粒径2倍时,柔性网将失去对SCC的阻隔作用。基于Bingham流体假设,建立了流动距离与渗入坝体体积之间的理论关系模型,由此确定的阻碍系数可以准确、有效反映柔性网对面层SCC流动的阻隔效果。

[Objective] Integrating the face slab and dam body using self-compacting concrete (SCC) in rock-filled concrete (RFC) dams can reduce formwork consumption and improve construction efficiency. This study aims to investigate the blocking effect of flexible meshes on the flow of face slab SCC into the dam body during integrated pouring, providing a scientific basis for the engineering selection of flexible mesh in RFC dam construction. [Method] An integrated pouring test was conducted on a typical section of an RFC dam. Self-compacting mortar was used to simulate high-strength face slab SCC for the erosion-resistant layer, while self-compacting paste was used to simulate low-strength dam body SCC for filling rock voids. Five flexible meshes with different aperture sizes (3 mm, 4 mm, 5 mm, 6 mm, and 8 mm) were designed, and hollow iron spheres were used to simulate rock aggregates. The flow distance, accumulation height, and infiltration volume of the model SCC into the rock voids under the barrier of the flexible mesh were investigated. [Result] (1) The blocking effect of flexible mesh on model SCC flow gradually weakened as the aperture increased. When the aperture increased from 3 mm to 8 mm, the flow distance of the model SCC into the dam body increased from 88.56 mm to 273.98 mm, the accumulation thickness increased from 88.81 mm to 155.21 mm, and the infiltration volume increased from 65.4 cm³ to 346.0 cm³.(2) A flexible mesh with an aperture equal to the maximum aggregate size (4 mm) most effectively prevented mortar from infiltrating and accumulating inside the dam body. As the aperture increased from 3 mm to 8 mm, the infiltration volume increased from 65.4 cm³ to 346.0 cm³. This indicates that 3 mm and 4 mm apertures provide the optimal blocking effect, whereas the 8 mm aperture provides the weakest.(3) The correlation coefficient between the experimental data and the theoretical formula exceeded 0.8, demonstrating good consistency and verifying that the theoretical model can effectively describe the flow and filling behavior of mortar inside the dam body. Under constant iron sphere parameters, as the aperture increased from 3 mm to 8 mm, the blocking coefficient decreased from 2.48 to 1.17, revealing that smaller apertures provide stronger blocking but lower filling efficiency. [Conclusion] Selecting a flexible mesh with an aperture equal to the maximum aggregate size can more effectively restrict the fluidity of SCC. Conversely, when the aperture exceeds twice the maximum aggregate size, the mesh loses its blocking effect on SCC. Based on the Bingham fluid assumption, a theoretical relationship model between flow distance and infiltration volume was established. The blocking coefficient derived from this model can accurately and effectively reflect the blocking effect of the flexible mesh on the flow of face slab SCC.