摘   要：为准确评估钢管混凝土界面脱空对其性能的危害，量化脱空风险并厘清其关键影响因素，本文采用MIDAS FEA NX软件模拟计算了钢管混凝土的脱空风险系数和脱空高度，并研究了钢管尺寸和混凝土性能对脱空的影响。结果表明：在相同混凝土性能的情况下，钢管直径越小，厚度越大，脱空风险就越大，脱空发生时间也越早，钢管直径越大，脱空高度越大，但在钢管直径相同的情况下，钢管厚度对脱空高度的影响较小；在相同钢管尺寸的情况下，混凝土的自收缩越大，脱空风险越大，脱空发生时间越早；混凝土中掺入膨胀材料可有效降低脱空风险，膨胀峰值越大，峰值时间越晚，抵抗脱空的效果越好；混凝土的绝热温升对脱空的影响较小。研究结果可为钢管混凝土设计、施工质量控制及服役期安全预警提供参考。Abstract: In order to accurately assess the harm of interface voids to the performance of concrete-filled steel tubes, quantify the void risk and clarify its key influencing factors, this paper adopts MIDAS FEA NX software to simulate and calculate the void risk coefficient and void height of concrete-filled steel tubes, and investigates the effects of steel tube dimensions and concrete properties on the occurrence of voids. The results show that under the same concrete properties, the smaller the steel tube diameter and the larger its thickness, the greater the void risk and the earlier the void initiation time. The larger the steel tube diameter, the higher the void height, while the steel tube thickness has a slight effect on the void height for concrete-filled steel tubes with the same diameter. Under the same steel tube dimensions, the greater the autogenous shrinkage of concrete, the higher the void risk and the earlier the void initiation time. Adding an expansive material to concrete can effectively reduce the void risk, and the larger the expansion peak value and the later its peak time, the better the anti-void performance. The adiabatic temperature rise of concrete exerts a minor influence on the generation of voids. The research results can provide a reference for the design, construction quality control and service period safety early warning of CFST structures.

杨睿,徐文.钢管混凝土脱空风险和脱空高度模拟及影响因素研究[J].混凝土与水泥制品,2026,53(5):113-119. YANG R,XU W,et al.Study on void risk, void height simulation and influencing factors of concrete-filled steel tubes[J].China Concrete and Cement Products,2026,53(5):113-119 (in Chinese).

摘   要：在混凝土浇筑过程中，钢筋密集区域易发生粗骨料堵塞现象，严重影响浇筑密实度与施工质量。为研究新拌混凝土间隙通过能力及堵塞风险的影响因素，基于离散元法（Discrete element method，DEM）搭建了仿真模型，结合J环试验验证了模型可靠性，探究了粗骨料形状和最大粒径、钢筋间距及混凝土体积对混凝土间隙通过能力与堵塞概率的影响。结果表明：搭建的DEM仿真模型可靠性良好，可有效表征新拌混凝土的间隙通过与堵塞行为；粗骨料形状、最大粒径、钢筋间距及混凝土体积均显著影响堵塞风险，其中，碎石的堵塞概率高于卵石，粗骨料最大粒径越大、钢筋间距越小、混凝土体积越大，堵塞风险越高，当钢筋间距增至90 mm时，无堵塞现象发生；堵塞概率计算结果与试验及仿真规律高度吻合，可为堵塞风险预判提供可靠数值手段。研究成果可通过合理调控相关参数降低钢筋密集区混凝土堵塞风险，为实际浇筑施工质量控制提供理论依据与技术参考。Abstract: During the concrete pouring process, coarse aggregate blockage is prone to occur in areas with dense reinforcement, which seriously affects the pouring compactness and construction quality. To investigate the factors influencing the void-passing capacity and blockage risk of fresh concrete, a simulation model was developed based on the discrete element method (DEM), and the reliability of the model was verified using the J-ring test. The effects of coarse aggregate shape and maximum particle size, reinforcement spacing, and concrete volume on the void-passing capacity and blockage probability were examined.  The results indicate that the developed DEM simulation model is reliable and can effectively characterize the void-passing and blockage behavior of fresh concrete. The shape of coarse aggregate, maximum coarse aggregate size, reinforcement spacing, and concrete volume all significantly influence the risk of blockage. Specifically, crushed stone exhibits a higher probability of blockage than pebble. The risk of blockage increases as the maximum coarse aggregate size increases, reinforcement spacing decreases, and concrete volume increases. When reinforcement spacing is increased to 90 mm, no blockage occurs. The calculated blockage probabilities are in close agreement with experimental and simulation results, providing a reliable numerical method for predicting blockage risks. The research findings can help reduce the risk of concrete blockage in areas with dense reinforcement by appropriately adjusting relevant parameters, thereby providing a theoretical basis and technical reference for quality control in actual concrete pouring operations.

黄灿,曹国栋,邓代强,等.基于离散元法的多因素条件下新拌混凝土堵塞规律研究[J].混凝土与水泥制品,2026,53(5):105-112,119. HUANG C,CAO G D,DENG D Q,et al.Study on blockage law of fresh concrete under multi-factor conditions based on the discrete element method[J].China Concrete and Cement Products,2026,53(5):105-112,119 (in Chinese).

蒋文涛，曹国栋.基于CFD-DEM的混凝土泵送压力损失研究[J].混凝土与水泥制品,2026,53(5):100-104. JIANG W T,CAO G D.Study on concrete pumping pressure loss based on CFD-DEM method[J].China Concrete and Cement Products,2026,53(5):100-104 (in Chinese).