At 9:06 a.m. on May 24, 2019, in Weifang, Shandong Province, the site of the second phase of the Yellow River East to West Water Diversion Project, the Bailang River bank was filled with cheers, which was a time worthy of celebration by all the participants in the project. The right side pipe jacking of Bailang River Pipe Jacking Project undertaken by SDWP was successfully completed all jacking work, the head of the machine precisely came out of the hole which means the completion of the Bailang River Double Line Pipe Jacking section. The record of double-line jacking diameter and one-time jacking distance of straight seam steel pipe in Shandong water conservancy project construction has been refreshed.
Bailang River pipe jacking project crosses 1305 m in length, the elevation from the river bottom is -0.49 m, the pipe elevation is - 10.38 m. The pipe jacking technology adopts the straight seam pipe with 9m length, DN2400, wall thickness of 30 mm to crosse the river bed bottom. The distance between the axes of the two top sections is 8.0m. Two pipe jacking machines are used to jack the pipe simultaneously on both sides, which is a super-long straight line pipe jacking. Pipe jacking is undertaken along a flat slope in the longitudinal direction. Pipe jacking passes through layers Ⅰ-④ of sandy loam with abundant confined water and contains ginger stone and shells. Due to the sea water intrusion, the soil salinity is serious and has moderate micro-corrosiveness.
Bailang River pipe jacking project is the most difficult and key control section for the second phase of the Yellow River East to West Water Diversion Project. In view of the characteristics of tight construction period, super-long jacking distance, large diameter jacking, complicated geology, high technical difficulty and high risk, the project department invites experts from well-known pipe jacking equipment manufacturing, construction and design industries in Shanghai to fully study and demonstrate the special construction scheme. In order to ensure safe and smooth jacking, the earth pressure balanced pipe jacking machine with the function of clearing obstacles and crushing is used to construct jacking equipment in this project, and a scientific and reasonable proportion test of drag reducing mud is carried out.
The working wells and receiving wells of Bailang River pipe jacking project were made twice and sinked twice by dry method. The earth pressure balance method is adopted in pipe jacking construction. The jacking of left side pipe was officially started on March 2 in this year, and the pipe passed through on May 13 with a period of 72 days. The jacking of right side pipe was officially started on March 6 in the same year, and finished on May 24 with a period of 80 days. During the construction period, when the right side pipe jacked in to 819 meters, it suddenly encountered confined water. There was the flowing soil and water gushing, the water pressure of the winch gate increased and the opening and closing of the winch gate got out of control. The situation was very critical. The construction site quickly took emergency and effective measures and immediately blocked it. The project department made a decisive decision, immediately called Shanghai pipe jacking experts and professional sub-contractor technicians to precisely determine the causes, adopted the replacement of winch gate, and reduced the gate size to ensure the smooth progress of jacking work.
The successful completion of the Bailang River pipe jacking project has solved the technical problems in the construction of long-distance and large diameter pipe jacking. Through the successful implementation of this project, SDWP has accumulated rich experience in the aspects of caisson production, sinking, machine head selection, jacking steel pipe welding, pipe jacking machine orientation measurement control, grouting coordination, thixotropic mud drag reduction, relay setting, tunneling soil transportation and so on. It has achieved high-intensity rush work and high-quality control, zero accidents in production safety.
                                                                                                                                          ( Editor：Zhang Qing and Cheng Cai)
Submitted by: Shandong water conservancy construction group co., LTD?????????????????????
Date: 24 May 2019?????????????????????????????????????????????????????????????????
Editor: ?Zhang Qing and Cheng Cai???? Issued by: Zhang dongmei??? ?Sent by: Ma Wenyuan?? Contact number: Zhang dongmei 15315378970?????????????????????????????????????????
Mail: zhangdm68@163.com????????????????????????????????????????????????????????
Contact number: Ma wenyuan 18453746582???????????????????????????????????????????
Mail: sdsjdqb@163.com????????????????????????????????????????????????????????????