沉入式圆筒结构变位临界值及变位计算

Critical Value and Calculation of Deflection for Embedded Cylindrical Structure

为探讨沉入式圆筒结构的变位临界值及其变位计算方法,采用模型试验实测圆筒结构变位值,分析圆筒转角θ与抗倾有效比η和推力矩MH间的关系,并推导了圆筒变位计算公式．试验研究表明,当转角θ≤0．2°时抗倾有效比η逐渐增大,并在θ≈0．2°时达到最大,此时圆筒抗倾能力最强;而转角θ>0．2°时,η和圆筒抗倾能力都明显减小．据此提出圆筒变位临界值θ=0．2°,此时,由转角θ产生的筒顶水平变位△1与筒高H之比为3．5×10-3．

The critical value of deflection for stability calculation of the embedded cylinder and the calculation method of deflection are studied. The deflections of the cylinder are measured by model tests. The relations between the inclined angle of cylinder, θ , and the moment of thrust, MH, and between θ and the effective antioverturning ratio, η, are discussed. Meanwhile, the calculation of the deflection of the cylinder is derived. It is obtained that, when the inclined angle of cylinder θ is no more than 0.2°, the effective anti-overturning ratio η increases gradually, and reaches its maximum at θ = 0.2°; when θ≈0.2°, the overturning-resisting capacity of the cylinder is the best; when θ 〉 0. 2°, η and the overturning-resisting capacity of the cylinder decrease evidently. So it is suggested that θ = 0.2° is the critical value for the deflection of the cylindrical structure. And when θ = 0.2°, the ratio of the horizontal displacement at the top of the cylinder,Δ1 , which is attributed to the inclined angle θ, to the height of the cylinder,H, is 3.5 × 10^-3.