Abstract: As a byproduct of urban pipe network construction, pipe jacking waste soil is characterized by large volume, strong regionallity, and complex composition. The pipe jacking waste soil is not easy to drain and consolidate due to its surface active ingredients, which restricts the refuse of waste soil resources. To address these problems, the waste soil generated by the pipe jacking construction of the underground comprehensive utility in Huanggang is used as raw materials to prepare selfcompacted pipe jacking controlled low strength materials (CLSM), and the change laws of its fluidity, bleeding rate, and compressive strength are studied by controlling the watersolid ratio, the cement to waste soil quality ratio, and the fly ash to cement (F/C) ratio. The test results show the following: (1) The watersolid ratio plays a major role in the fluidity change of CLSM, while the compressive strength decreases with the increase of F/C, and increases with an increase in cement to waste soil quality ratio. (2) By controlling the watersolid ratio, the cement to waste soil quality ratio, and F/C ratio, selfcompacting and highfluidity materials with fluidity of 100~200 mm, bleeding rate of less than 3%, and compressive strength of 0.35~0.7 MPa can be prepared, which meets the requirements of the trench backfilling process in terms of working performance and strength.

Key words: pipe jacking waste soil, controllable low strength materials, fluidity, bleeding rate, compressive strength