Abstract:

During the construction of smallspacing rectangular pipe jacking in an underground parking lot constructed by cut and convert (CC)method, problems such as the pipejacking machine declination and difficulty in controlling the jacking attitude often occur. Therefore, the causes for jacking declination and attitude deviation are theoretically analyzed based on attitude monitoring data, and corresponding control measures and field test are carried out. The results show that: (1) The causes for declination include machine body weight deviation, slurry leakage, insufficient attitude reservation and unstable backrest. (2) The declination can be effectively prevented by adopting measures such as equipment and pipe segment positioning, door sealing treatment, initial attitude reservation increasing and backrest stability control. (3) The door reservation and cutting during launching phase and boring speed control and Eshaped guide groove for axis control during jacking phase can effectively control the jacking attitude. (4) By adjusting the stroke difference of the articulated cylinder and the main push cylinder and the earth pressure along the direction of the attitude deviation, good effect has been achieved.

Key words: shallowcovered and smallspacing tunnel, rectangular pipejacking, structural cut and convert (CC) method, declination prevention, boring attitude control, boring attitude adjustment