Pile foundation construction technology of "Highway and Railway Large Bridge Construction Project"

     In recent years, with the implementation of the grand blueprint of the country’s vertical and horizontal transportation network, and the steady progress of the “One Belt, One Road” national strategy, high-standard and high-standard unprecedented construction of river, lake and sea transportation hubs and cross-sea bridges, high-speed railways and With the rapid development of highway construction, our company keeps up with the trend of the times, increases its technical reserves, and spends huge sums of money to introduce new technology and new equipment, and strive to build a "pile of excellent equipment, excellent technology, talent gathering, and first-class service". A leading enterprise in the field of foundation construction". The following is a brief introduction to the construction of large-scale highway and railway bridge pile foundation projects undertaken by our company in the past ten years.

     Typical Project (1) From September 2000 to March 2001, the company undertook the "Runyang Yangtze River Bridge"-"F4 Pylon Foundation Rock-Socketed Pile Project" located on the side of Runzhou District, Jiangyin, Jiangsu. Photo on the left: Shen Put a φ3200mm steel protective tube (Note: the rock-socketed diameter is φ3000mm), the photo on the right: QJ3000 rotary drilling rig is set on a "Bellet frame" that can move in plane sliding.

     Typical project (2) From 2012 to 2013, our company undertook the construction tasks of "Hong Kong-Zhuhai-Macao Bridge Island Tunnel Project", "East Artificial Island" and "Non-Navigable Bridge Pier Rock-Socketed Pile Project" connecting Hong Kong direction. Six full-hydraulic rotary drilling rigs were invested, and the construction of 78 rock-socketed piles with L=65～90m and Φ2200mm～Φ2800mm bridge pier foundations was successfully completed.

     Typical project (3): Following the completion of the "Shuangdao Port Bridge Overwater Rock-socketed Pile Project" from October 2012 to June 2013 on the Weihai-Yantai Section of the Qingrong Intercity Railway, the company undertook it from 2015 to 2016 The construction project of "Qianzhangchang Railway "Apengjiang Bridge" 0#—19# all pier rock-socketed piles" located in Qianjiang, Chongqing, where 16#—19# and 0#—13# are bridge piers with large and small mileage (note: 13#, 16#, 17#, 18# piers are all Φ2.5m rock-socketed piles); among them, 14# piers and 15# piers are the main bridge piers (cable-stayed bridges with two piers up to 182m in height after completion, "under construction The upper structure of the main bridge piers". The main bridge piers are each 36 (roots) Φ2.5m, and the pile length is 85～96m (design effective depth, construction depth is generally increased by 4～6m); the remaining bridge pier piles are respectively Φ1.5m～2.5m, The number of piles is 135 (pile), and the pile length ranges from 36m to 67m. The construction scene of the pile foundation of the 14# main bridge pier, the SR385R rotary excavator invested by our company; the construction scene of the 15# main bridge pier (concrete pouring with dual pump trucks). The pile length of the main bridge pier has far exceeded the working depth of the rotary excavator, and the strength of the lower rock is about 110map). For this reason, 9 percussion drilling rigs of 14 to 16 tons were put into the two main piers to replace and complete the drilling depth (this is based on actual Under the circumstances, the combination of two types of drilling rigs was used flexibly, and very good results were achieved), and a SR280R rotary excavator was put into operation later.

     Typical projects (4th and 5th) From 2015 to the beginning of 2018, our company successively undertook the pier pile foundation projects of the "Zhaohua" and "Yangmeizhou" highway bridges on the Xiangjiang River in Xiangtan, Hunan. "Zhaohua Bridge" has 206 rock-socketed piles of Φ1.8m～Φ2.8m. The construction features are: (1) The pile foundations of the 7 water bridge piers are all located in the bare rock area; (2) The construction procedures for the pile foundations of the water bridge piers are: Steel cofferdam construction—→steel casing installation—→concrete bottom sealing in the cofferdam—→rock-socketed pile construction—→delivery of superstructure construction; (3) mainly percussive drilling rigs. "Yangmeizhou Bridge" (Note: The approach bridge on the west side, including the pile foundations of the main bridge piers on the east and west sides, is constructed by our company, and more than 100 piles on the land on the east side are constructed by other teams) The workload is Φ1.5m～Φ3.0m rock-socketed 276 piles (including 22#, 23# water main bridge piers 24×2=48 Φ3.0m rock-socketed piles, and 3 approach piers are located on the crosswalk river, the rest are land piers), "Yangmeizhou Bridge" The construction features are: (1) The water main bridge piers are first constructed on the water "occluding steel pipe pile cofferdam"—→backfilling part of the soil in the cofferdam, sinking the steel casing, completing the backfilling operation—→installing the drilling rig, forming holes, Follow-up with steel casing—→rock-socketed pile construction—→delivery of superstructure construction; (2) "The pile foundations on the west side of the bridge are basically in the "karst cave area", and most of the pile foundations are located in the "beaded cave geology". The maximum value of the depth is more than 25m, so the construction of the pile foundation on the west side of the bridge is very difficult; (3) The construction of the bridge pier pile foundation on the crossway river first builds the water channel and the bridge pier pile foundation construction platform—→steel protective tube sinking—→embedded Rock pile construction—→delivery of the superstructure construction; (4) Since a large number of pile foundations are in the cave area, our company carefully planned and organized the rotary drilling rig, the full set of rotary drilling rigs, and the impact drilling rig into the pile foundation hole construction; (5) ) In order to grasp the geological cave conditions, the company invested in XU1000 drilling rigs to conduct one-pile, one-hole exploration operations; (6) According to the cave conditions of each pile, specific construction measures and directional operation protection techniques were formulated.