Pipe Ramming is a process utilized primarily for the crossing of roads, highway sections, and railroads. This pipe construction method can be thought of as a horizontal pile driving operation in a sense, where an air compressor operated hammer drives a steel casing pipe horizontally from a drive shaft to the receiving shaft. The dynamic energy of a percussion hammer attached to the end of the casing pipe is used to install the pipe from a drive pit to a reception pit. The borehole is not created by the ramming equipment, but rather, by hammering the open ended pipe through the soil. When the crossing is complete, the spoils inside the casing pipe are removed using air or fluid pressure and mechanical means such as a compact excavator.
One of the greatest advantages of pipe ramming is that the casing pipe provides a continuous soil support during the hammering process, therefore negligible overall disturbance to the pipe-soil system is sustained. This makes pipe ramming particularly suited to applications where critical surface structures, such as railroads or highways, are being traversed. Due to the lack of a precise guidance system, pipe ramming is suited for relatively short crossing runs, with 250-ft being the ideal distance, and 500-ft being a typical upper limit.
The Permalok® interlocking push joint is an ideal replacement for traditional steel casing pipe which must undergo the time consuming field butt-welding prior to installation. The interference fit joints of Permalok® are engaged during the hammering process, saving time for the Contractor and resulting in financial savings. Permalok® has been successfully used for road and highway crossings by most departments of highway nationwide, coast to coast. Similarly, all major railway companies have specified and successfully utilized Permalok®, including BNSF, Union Pacific, Peoria & Pekin, Metra, amongst a host of others.