Ring stiffness is used to indicate the external pressure resistance of buried PPR hot water insulation pipe. If the ring stiffness of PPR hot water insulation pipe is too small, the pipe may be seriously deformed or destroyed by buckling. If the ring stiffness is too high, too large section moment of inertia will be adopted, which will lead to too many materials and increase the cost.

PPR熱水保溫管接受的負(fù)載有內(nèi)部壓力和外部壓力，通常內(nèi)部壓力產(chǎn)生的應(yīng)力是形成PPR熱水保溫管毀壞的主要緣由，毀壞方式是管壁內(nèi)的拉應(yīng)力形成變形過大和決裂，設(shè)計的時分，要先按接受內(nèi)壓負(fù)載停止計算，選擇資料和構(gòu)造數(shù)據(jù)，然后再思索外壓負(fù)載停止設(shè)計驗算，必要時要修正構(gòu)造數(shù)據(jù)。

The load that PPR hot water insulation pipe receives includes internal pressure and external pressure. Usually the stress produced by internal pressure is the main reason for the damage of PPR hot water insulation pipe. The damage mode is that the tensile stress in the pipe wall causes excessive deformation and fracture. When designing, the calculation should be stopped according to the load received by internal pressure, the data of selection and construction should be selected, and then the design test of the load stopped under external pressure should be considered. Calculate, revise the construction data when necessary.

PPR熱水保溫管接受外壓負(fù)載，毀壞方式是外壓負(fù)載形成管材變形過大或壓屈失穩(wěn)，設(shè)計時要依照外壓負(fù)載停止計算，來選擇資料和構(gòu)造數(shù)據(jù)。

PPR hot water insulation pipe receives external pressure load. The damage mode is that the external pressure load causes excessive deformation or buckling instability of the pipe. The design should stop calculating according to the external pressure load to select data and structural data.

外壓負(fù)載比擬復(fù)雜，包括土壤重量和空中產(chǎn)生的靜負(fù)載，及運輸車輛經(jīng)過時產(chǎn)生的動負(fù)載，PPR熱水保溫管接受負(fù)載的機理也是比擬復(fù)雜的，由于PPR熱水保溫管屬于柔性管材，在外壓負(fù)載作用下，管材和四周的土壤會產(chǎn)生“管土共同作用”，也就是說管材和四周土壤來共同接受外壓負(fù)載。

External pressure load comparison is complex, including soil weight and static load generated in the air, and dynamic load generated by transportation vehicles. The mechanism of PPR hot water insulation pipe receiving load is also complex. Because PPR hot water insulation pipe belongs to flexible pipe, under the external pressure load, pipe material and surrounding soil will produce "pipe-soil interaction", that is, pipe material and surrounding soil. To jointly accept external pressure load.

PPR熱水保溫管的環(huán)剛度實踐上是不斷不變的，比方de110*0.8Mpa和de315*0.8Mpa的PPR熱水保溫管，同樣重量壓力的管道，但環(huán)剛度并不是相同的，管材的口徑越大，環(huán)剛度就會相對削弱，還有氣溫變化的影響，溫度降落，PPR熱水保溫管的硬度也會增大，環(huán)剛度就會變大。

In practice, the ring stiffness of PPR hot water insulation pipes is constant. For example, de110*0.8Mpa and de315*0.8Mpa hot water insulation pipes, the same weight pressure pipes, but the ring stiffness is not the same. The bigger the diameter of pipes, the weaker the ring stiffness will be. There is also the influence of temperature changes. When the temperature falls, the hardness of PPR hot water insulation pipes will increase, and the ring stiffness will increase.

關(guān)于PPR熱水保溫管性能的理解，能夠協(xié)助人們更好的運用PPR熱水保溫管，使之發(fā)揮更大的價值，而PPR熱水保溫管廠家在設(shè)計和消費時，也會思索PPR熱水保溫管的環(huán)剛度問題，保證管材性能的穩(wěn)定。

Understanding the performance of PPR hot water insulation pipe can help people better use PPR hot water insulation pipe and make it play a greater value. When designing and consuming PPR hot water insulation pipe manufacturers will also consider the ring stiffness of PPR hot water insulation pipe to ensure the stability of pipe performance.