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预应力砼压力管,在制订和修订国标时,复土深度均按2m考虑。但在管线实际铺设时,局部线段却经常超过此值,特别是在以外压为主的条件下使用(如涵管)。对此,人们需要了解管体的外压承载能力。由于国标未列外压能力要求,一般不做外压检验。抵抗外压能力的理论计算值,未经验证,可靠与否,把握不大。为了解决这一疑虑,我以国标规定的“抗裂检验压力”(内压)作为主要参数推导出了与集中荷载有直接关联的计算式。只要内压试验合格,据此计算的抵抗集中荷载的能力就应该是可靠的,即等于作了间接试验。内压试验合格,即表明混凝土强度及环筋预应力对管体形成的预压应力得到了综合保证,在同断面上承担集中外压的能力,同样以这种综合能力为依据,也应该得到同样的保证。
Prestressed concrete pressure pipe, in the formulation and revision of the national standard, the depth of complex soil are considered in 2m. However, when the pipeline is actually laid, the local line segment often exceeds this value, especially when the external pressure is dominant (such as culvert). In this regard, people need to understand the external pressure carrying capacity of the pipe body. As the national standard does not list the requirements for external pressure, no external pressure test is generally performed. The theoretically calculated value of resistance to external pressure is unverified and reliable or not. In order to solve this doubt, I used the “resistance to crack test pressure” (internal pressure) specified by the national standard as the main parameter to derive a formula that is directly related to the concentrated load. As long as the internal pressure test is acceptable, the ability to resist concentrated loads based on this calculation should be reliable, which means that it is equivalent to making indirect tests. Passing the internal pressure test indicates that the concrete strength and prestress of the ring tends to provide comprehensive assurance for the pre-compression stress on the pipe body. The ability to carry out the external pressure on the same section is also the basis for this comprehensive ability. The same guarantee.