The southern section of the Macau Light Rapid Transit East Line project is a joint venture of China State Construction Engineering (Hong Kong) Limited Macau Branch, China State Construction Engineering (Macau) Limited, and Shanghai Tunnel Engineering Co., Ltd. - Macau Branch.

This project comprises three stations and three running tunnels. The stations are ES4, ES5, and ES6, and the running tunnels are the ES4–ES5 section, the ES5–ES6 section, and the ES6–LRT Taipa Line Ferry Terminal Station section. ES4 and ES5 are located in New Town Zone A, connecting the central and southern parts of New Town Zone A; ES6 is located in New Town Zone E, connected to New Town Zone A by an undersea tunnel.

Schematic diagram of the Macau East Line LRT alignment plan

New Town Zone A

New Town Zone E

To prevent trench wall instability and collapse during diaphragm wall construction in soft soil layers, φ850@600 triple-axis cement mixing piles are used as a reinforcement measure to treat the soil on both sides of the diaphragm wall. The overall construction sequence is to give priority to ES6 station trench wall reinforcement → ES5 station trench wall reinforcement → ES4 station trench wall reinforcement, or alternatively to give priority to ES6 station trench wall reinforcement → simultaneous construction of ES5 and ES4 trench wall reinforcement. The actual construction arrangement shall be determined according to actual conditions.

According to the geological survey data completed to date for the LRT East Line construction project, the geological stratification within the site area consists, from top to bottom, of fill sand, marine sedimentary soil, alluvial soil, boulders, completely/highly weathered granite, and moderately/slightly weathered granite, among which the marine sedimentary clay is very soft to soft clay. The depths of the triple-axis mixing piles at the three stations are mainly distributed in the fill sand and marine sedimentary soil; the average thickness of the fill sand is about 12 m, and the average thickness of the marine sedimentary soil is about 6.7 m.

Table of basic parameters of triple-axis mixing piles

The main construction task this time is the trench wall reinforcement by triple-axis mixing piles at the three stations ES4, ES5, and ES6, with three sets of equipment deployed simultaneously.
ES6 Station is the shield launching station and is given priority in construction, with a total of 412 piles, approximately 6,600 ㎡, and an average pile length of 10.7 m. Construction started on October 6, 2023, using single-shift operation.

ES5 Station has a total of 412 piles, approximately 8,894 ㎡, with an average pile length of 14.4 m. The piling rig has currently passed third-party mechanical engineer inspection and trial piling was conducted on November 12, using double-shift operation, with a planned construction period of 20 days.

ES4 Station has a total of 638 piles, approximately 13,800 ㎡, with an average pile length of 14.5 m. The piling rig is currently being assembled, and construction is planned to start in mid-October, with a planned construction period of 40 days.

This project is another foundation engineering project in which Shanghai Guangda is participating in Macau. From winning the bid to personnel certification, equipment customs clearance, personnel and equipment mobilization and assembly, and commencement of construction, Shanghai Guangda has consistently and efficiently implemented the tasks assigned by the general contractor, steadily advancing preliminary preparations and creating favorable conditions for smooth construction. Throughout the entire construction process, Shanghai Guangda will also hold itself to strict standards, humbly accept supervision from all project parties, and, on the premise of ensuring safe production, strive to complete its assigned construction tasks ahead of schedule and win recognition from all participating parties.