| 摘要: |
| 为了获得缠丝后PCCP管芯的预压应力大小，本文首先介绍了规范中的计算方法，然后基于弹性力学中圆环或圆筒受均布压力理论给出了管芯各部位的环向应力计算公式。同时利用有限元软件Abaqus选取合适的材料本构，建立了管芯二维平面计算模型。另外设计了现场管径800 mm的内衬式PCCP缠丝过程管芯混凝土层内表面应变测试原型试验，获得了沿管长方向两个1/4处以及中间位置等三个测点的缠丝后混凝土层内表面应变值。将试验结果与三种计算方法的结果进行对比分析，结果表明：规范、弹性力学和有限元方法计算的管芯混凝土层内表面预压应力分别为22.61 MPa、25.86 MPa和26.01 MPa，实际试验测得的结果为25.34 MPa，后两种方法计算结果与实际试验结果吻合良好，误差在5%以内，使用后两种方法计算管芯混凝土层预压应力更为合理。钢筒层的环向应力则是规范方法计算结果较另外两种方法计算结果偏大，设计时可使用弹性力学或有限元方法。三种方法计算的缠丝后钢丝拉应力结果基本接近，采用任何一种方法来计算钢丝的受力都是可行的。研究成果可为PCCP工程设计人员参考。 |
| 关键词: 管芯 应力 弹性力学 现场试验 |
| DOI： |
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| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目）；国家重大科研仪器研制项目；江苏省第五期“333工程”培养资金资助项目 |
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| Calculation method of precompression stress of the core after PCCP wrapping |
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Sun Yueyang, Hu Shaowei
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Nanjing Hydraulic Research Institute
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| Abstract: |
| This study initially introduces a calculation method in the specification to obtain the precompression stress of the core in PCCP after being wrapped. Moreover, the formula for calculating the circumferential stress of each part of the core is given based on the theory of uniform pressure distribution in elastic mechanics. The suitable material constitutions are selected, and a –two-dimensional calculation model is established using Abaqus. In addition, a field test of a lined PCCP with diameter of 800 mm is designed to obtain the strain of the inner surface of the concrete layer during prestressing. The strain values at three measuring points, that is, two quarter-pipe lengths and the middle position, are presented. Results show that the precompression stresses on the inner surface of the concrete layer of the core calculated by code, elasticity, and finite element methods are 22.61, 25.86, and 26.01 MPa, respectively; the actual test result is 25.34 MPa, which is in good agreement with those calculated by the last two methods with error within 5%. Thus, using the latter two methods for the calculation of the precompression stress of the concrete layer of the core is reasonable. The circumferential stress of the cylinder calculated by the code method is larger than those of the other two methods. Hence, the elastic mechanics or finite element method can be used for designing the cylinder. Results of tensile stress of wire after winding by the three methods are close to one another, and calculating the force of wire using any of the methods is feasible. The results of this study have some reference value for engineers of PCCP projects. |
| Key words: core stress elastic mechanics field test |
