As a key infrastructure project promoting the integrated development of Shanghai and Jiangsu, the Taicang pilot section of the Suzhou-Wuxi-Changzhou Intercity Railway is attracting significant attention. SEMW?machinery and equipment are deployed wherever needed. Recently, a DMP-type mixing pile test operation at the construction site of the Suzhou-Wuxi-Changzhou Intercity Railway’s Suzhou-Taicang pilot section has garnered significant attention and injected significant momentum into the project.

?

The Taicang pilot section project of the Suzhou-Wuxi-Changzhou intercity railway is a key step for Taicang City to promote and improve the regional comprehensive transportation system, connect to the Yangtze River Delta railway artery, and create a gateway transportation hub. It will have a profound impact on the cooperative development between Shanghai and Jiangsu. It not only accelerates the process of Shanghai-Jiangsu integration, but also is a key step in accelerating integration into the integrated development of the Yangtze River Delta. It is of great significance!

Project Introduction

The Taicang pilot section of the Suzhou-Wuxi-Changzhou Intercity Railway is 10.3 kilometers long. It originates from Taicang Station and runs along Zhanqian Avenue, Jiangnan Road, and Xingye Road to the provincial border, where it connects with the northern extension of the Shanghai Urban Rail Jiamin Line. Within Taicang, there are three stations: Taicang Station, Baiyundu Road Station, and Shibagang Road Station, as well as a vehicle depot.

The underground section between Baiyundu Road Station and Shibahong Road Station runs westward along Jiangnan Road after exiting Baiyundu Road Station, passing under the Hujiagang River (Bridge), and turning south near the Yanjiang Expressway. It then crosses Shibagang Road and emerges underground, becoming an elevated section connecting to Shibagang Road Station. This project involves reinforcing the tunnel interface and end caps of the shield tunnel section between Baiyundu Road Station and Shibagang Road Station.

This project is more than just a railway extension; it represents a unique and fruitful path for collaborative development between Shanghai and Jiangsu. For such a significant railway infrastructure project, meticulous construction is crucial. After rigorous selection and extensive research by the client, SEMW?Machinery’s DMP mixing pile equipment was selected as the primary reinforcement equipment. The equipment is currently involved in the project’s construction and has completed the pile test phase.

?

DMP Method Mixed Pile Arrangement

Based on the geological and hydrogeological conditions of this project, as well as the successful experience of similar large shield tunnel end reinforcement in Suzhou and other regions of China, this project’s shield tunnel end reinforcement, tailored to the strata, utilizes an external mixing pile water-stop curtain, ground jet grouting, and mixing piles for the long-distance end of Baiyundu Station and the short-distance end of the working shaft. Digital micro-disturbance mixing piles (DMP method) with a diameter of 850@650 mm and high-pressure jet grouting are used for reinforcement, supplemented by water reduction measures. The reinforcement area extends 18 meters along the route and extends 5 meters from the tunnel’s outer edge (top to ground level). The piles are 27.184 meters long, with a cement content of 20%. The reinforced volume for each working shaft is approximately 11,000 cubic meters.

Overcoming Three Construction Difficulties

?

Shield tunnel entry and exit is a technically challenging and complex phase of shield construction. Improper handling can easily lead to soil collapse and loss outside the tunnel portal, causing water and sand inflow, ground subsidence, and even loss of shield control. To ensure safe tunnel entry and exit, ground reinforcement is required at the tunnel entry and exit points.

?

Difficulty 1: Large Shield Diameter, High Reinforcement Requirements

The shield tunnel for this project has a relatively large diameter of 13.6 meters, necessitating high requirements for tunnel portal reinforcement. Improper handling can pose significant safety risks to shield construction.

?

The DMP method mixing pile equipment utilizes controlled mixing blade rotation and four drill rods that simultaneously inject slurry and gas to achieve automated pile construction. The equipment automatically controls ground pressure and uses pressure relief channels formed on the outer sides of the rotating, shaped drill rods to achieve micro-disturbance construction, effectively ensuring uniformity and higher quality of the pile.

?

Difficulty 2: Poor Geology, Prone to Misalignment and Leakage

The shield tunneling area is primarily composed of poor-quality silty soil and highly permeable silt. The silty soil is soft and prone to shield misalignment, while the silt’s high permeability makes it prone to leakage. This places high demands on the quality of the reinforced material.

The DMP method mixing pile equipment uses a digital construction control system to precisely control the entire pile construction process. It monitors parameters such as shotcrete pressure, slurry flow, jet pressure, ground pressure, pile depth, pile speed, and pile verticality in real time, ensuring strict compliance with design standards. This not only addresses the problem of pile misalignment in this stratum, but also ensures excellent pile quality even in deep silt layers.

?

?

Difficulty 3: Unique strata prone to water seepage

The silt at the bottom of the shield tunnel is slightly confined water, requiring the reinforced material to possess not only high impermeability but also sufficient strength.

The DMP method mixing pile equipment features an automatic slurry preparation and supply system that accepts commands from a digital construction management system. Equipped with flow and pressure measurement devices, it automatically measures slurry volume and automatically completes the construction process, including slurry preparation and supply, mixing, shotcrete spraying and jetting, sinking and lifting, and flushing the shotcrete pipe. Through automated construction control, construction parameter recording, and monitoring and early warning of the pile construction process, the impermeability and strength of the pile are ensured.

?

???

Important railway infrastructure projects are arduous tasks that can only be undertaken by truly capable people. After a week of intensive pile trials,?SEMW’s DMP method mixing pile equipment completed the trial tasks safely, efficiently and environmentally friendly with its ultra-high stability and excellent pile quality, winning praise and recognition from the owner.

??

In the future, this Suzhou-Wuxi-Changzhou intercity railway hub, carrying the high-quality development of the Yangtze River Delta integration, will witness the surging momentum of Shanghai-Suzhou integrated development. SEMW?Machinery will continue to use its innovative power to help China’s infrastructure move towards higher quality.