振捣深度对新浇筑混凝土模板侧压力影响研究

THE INFLUENCE OF VIBRATION DEPTH ON FORMWORK LATERAL PRESSURE OF FRESH CASTING CONCRETE

目前关于振捣深度对模板侧压力影响的研究还很少,各国标准中关于振捣深度及超深振捣模板侧压力的规定也存在较大差异。为此,设计了5个60 cm×60 cm×300 cm柱体试件和2个30 cm×120 cm×300 cm墙体试件,研究了振捣深度和二次超深振捣对模板侧压力的影响,提出了混凝土超深振捣的定义。研究表明:振捣深度或二次超深振捣对模板侧压力有较大影响,超深振捣会大幅度增加混凝土对模板的侧压力,对模板工程的安全造成不利影响。但超深振捣位置处的模板侧压力并不随振捣深度的增加而线性增加,其值明显小于将混凝土视为纯液体计算得到的压力值。

There is few research of vibration depth influence on formwork lateral pressure of fresh casting concrete at present. There is also big difference in the regulation of lateral pressure on formwork due to the vibration depth or ultra-deep vibration among standards of different countries. For this reason,five column specimens of 60 cm × 60 cm ×300 cm and two wall specimens of 30 cm × 120 cm × 300 cm were designed to study the lateral pressure on formwork influenced by the depth of vibration and ultra-deep revibration,and then the definition of the ultra-deep vibration was put forward. The experiment results showed that the lateral pressure was greatly affected by the depth of vibration or ultra-deep revibration. The ultra-deep vibration could greatly increase the lateral pressure and would have adverse impact on the safety of the formwork project inevitably. But the lateral pressure on formwork in the position of ultradeep vibration was not linearly increased with the increase of vibration depth,whose value also obviously less than the pressure calculated as the hydrostatic pressure produced by a fluid with concrete density.