What Does Strain Rate Mean?
Strain rate in the context of a steel casing pipe can be defined as the rate at which strain or the deformation of the pipe with respect to time occurs.
In the trenchless construction method of pipe ramming, a steel casing is used before the product pipe to drive it into the ground with blows from the ramming unit. Installation of pipes using the pipe ramming method can be optimized by assessing the efficiency of the connection between the hammer and the casing pipe.
Trenchlesspedia Explains Strain Rate
Steel, which is an alloy of iron and carbon, exhibits desirable behavior when subjected to impact loading. The ductility, yield strength, compressive strength, and strain rate of steel allow it to undergo the rigorous ramming process with little to no deformation.
Steel casings also possess a relatively low coefficient of friction; thus minimizing resistive forces as the casing is driven through the soil. The ring stiffness of the casing also provides adequate support for the upper layers of soil to reduce the probability of subsidence or settlement.
A low-efficiency energy transfer from the hammer to the casing pipe can result in a slow penetration or no penetration at all. On the other hand, high or excessive energy transfer can result in damage to the casing pipe. The transfer of energy from the hammer to the pipe can be lost to some extent due to friction and heat. The maximum transfer of energy depends on the alignment of the hammer, the connection between the hammer and the pipe and the tension in the cables.