Construction Productivity Advancement Research (CPAR) Program: Controlled FieldTests of Retrievable Microtunneling System with Reaming Capabilities

摘要

The McLaughlin/Markham microtunneling system tested at the U.S. Army EngineerWaterways Experiment Station test facility has all the capabilities of conventional microtunneling systems, with the additional capability for retrieval and reaming. Both of these unique capabilities were evaluated under documented, controlled ground conditions. These tests clearly demonstrated the ability of the system to maintain stability of the excavation face during retraction of the machine through flooded, running sand. The test also demonstrated the capability of the system to successfully install upsized pipes using the reamer assembly. The versatility of this system offers intriguing possibilities with regard to critical applications. In addition, these tests provided an opportunity to gain a better understanding of ground deformations and jacking forces associated with microtunneling. Methods for predicting and controlling ground deformations were evaluated. The influence of lubrication on jacking forces was assessed, along with the influence of different ground conditions on jacking forces.