a. Graduate Student, Kvushu University
b. Graduate Shools of Engineering, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan

Recently, for the concern of safety in constructions as well as for environmental and economical reasons, an efficient small-diameter shallow tunneling method has become increasingly important for outside plant engineering such as water supply, gas, electricity, telecommunications. In particular, for construction work near existing facilities, an underground tunnel excavated by the pipe-jacking is becoming increasingly popular to avoid adverse effects.
Basically, the pipe-jacking system is involving the pushing or thrusting of the drivage machine through the concrete pipes ahead of jacks. The method utilizes the mud slurry that is formed around the pipes or stability of surrounding soil. However, it is not well understood the behavior of the soils and mud slurry around the pipes.
From this point of view; this paper discusses the effect of mud slurry and stability of surrounding soil by means of the fundamental property tests and the laboratory tests. Moreover, this paper analyzed the performance of the behavior of mortar and mud slurry as the rehabilitation method* *by means of two-dimensional Eulerian-Lagragian seepage analysis.