Engineering Service
MJS All-Directional High-Pressure Jet Grouting
MJS全方位高压喷射注浆工法
MJS (Metro Jet System) combines high-pressure jet grouting with forced in-hole slurry discharge and in-ground pressure monitoring. By regulating slurry discharge during ground treatment, it limits construction-induced disturbance and supports ground improvement near existing metro tunnels, beneath overhead power lines, and at other constrained or sensitive sites.
MJS（Metro Jet System）全方位高压喷射注浆工法，将高压喷射注浆、孔内强制排浆与地内压力监测相结合，通过调节排浆量控制施工扰动，适用于既有地铁邻近、高压线下方及其他空间受限、环境敏感条件下的地基加固。
Supplied by Zhejiang Datong Construction Technology Co., Ltd.
Overview
Service overview
MJS uses a multi-port drill string and a dedicated jetting monitor to cut and mix the in-situ soil with high-pressure cement grout. Spoil slurry is forcibly discharged through a dedicated path, while in-ground pressure is monitored and regulated by adjusting the discharge volume. This integrates ground treatment with control of the pressure changes that can cause surface heave, settlement, or movement of nearby structures.
The method supports vertical, horizontal, and inclined jet grouting. Treatment direction, extent, cement content, and pile arrangement are selected to suit the ground conditions, structural layout, and protection requirements. Applications include ground treatment near existing tunnels, beneath box culverts and municipal structures, and in or around deep excavations.
Project delivery focuses on the relationship between jetting, slurry discharge, and in-ground pressure, together with verification of the treated-ground geometry and monitoring of adjacent structures. The objective is to achieve the specified ground improvement while controlling effects on the surrounding environment.
MJS 工法采用多孔管和专用喷射装置，通过高压水泥浆切削、搅拌原状土，形成水泥土加固体。施工过程中，废浆经专用通道强制排出，并依据地内压力监测情况调节排浆量，将土体加固与压力控制结合起来，降低地表隆起、沉降及邻近结构变形的风险。
该工法可进行竖直、水平及倾斜喷射注浆，结合地层条件、结构布置与保护要求确定施工方向、加固范围、水泥掺量和布桩方式，可用于既有隧道邻近加固、箱涵及市政结构基础处理，以及深基坑周边或坑底加固。
工程实施重点关注喷射、排浆与地内压力之间的关系，并结合加固体几何尺寸检查和邻近结构监测，在达到加固要求的同时控制对周边环境的影响。
Scope
Service scope
Key components that may be provided for relevant engineering scenarios.
- Multi-port drill string and dedicated monitor for integrated jetting and slurry discharge
- Forced in-hole slurry discharge with in-ground pressure monitoring and regulation
- Control of construction-induced ground movement and effects on nearby structures
- Vertical, horizontal, and inclined treatment to suit constrained underground geometry
- Treatment zones and cement content tailored to structural and ground-improvement requirements
- Construction control integrating jetting parameters, slurry discharge, and deformation monitoring
- 多孔管与专用喷射装置配合，实现喷射注浆与排浆协同作业
- 孔内强制排浆，结合地内压力监测进行调控
- 控制施工引起的地层变形及对邻近结构的影响
- 支持竖直、水平和倾斜施工，适应复杂地下空间
- 可按不同结构部位确定加固范围和水泥掺量
- 结合喷射参数、排浆情况与变形监测开展施工控制
Scenarios
Applicable project scenarios
Typical project conditions where this offering may be relevant.
- Ground improvement above or beside existing metro tunnels and within tunnel protection zones
- Sites beneath overhead power lines or with restricted headroom and equipment access
- Foundation treatment beneath box culverts, underpasses, and municipal structures
- Ground improvement and groundwater cutoff in or around deep excavations
- Works near buildings, underground utilities, and other movement-sensitive assets
- Treatment requiring vertical, horizontal, or inclined jet grouting
- 既有地铁隧道上方、侧方及保护区内的地基加固
- 高压线下方、低净空或设备进场受限的施工场地
- 箱涵、地下通道及市政结构底部地基加固
- 深基坑坑底、坑外或局部高风险区域止水与加固
- 对地表变形、邻近建筑或地下管线控制要求较高的项目
- 需要竖直、水平或倾斜喷射注浆的复杂工况
Offering Details
Technical Details & Applications
Method Principle and Pressure Control
MJS (Metro Jet System) cuts and mixes the ground with high-pressure cement grout through a multi-port drill string and a dedicated jetting monitor. Alongside grout injection, spoil slurry is forcibly discharged from the bore and in-ground pressure is monitored.
Adjusting the slurry-discharge volume helps control pressure changes in the ground. The method therefore manages jetting and discharge together, rather than treating slurry removal only as a surface-handling operation. This is particularly relevant where construction-induced ground movement could affect existing tunnels, foundations, or underground utilities.
技术说明与应用案例
工法原理与地内压力控制
MJS（Metro Jet System）全方位高压喷射注浆工法，利用多孔管和专用喷射装置，以高压水泥浆切削、搅拌地层，同时实施孔内强制排浆和地内压力监测。
通过调节强制排浆量，控制注浆过程中地内压力的变化。因此，排浆不仅是地面废浆处理环节，也是施工扰动控制的重要组成部分，尤其适用于邻近既有隧道、基础及地下管线等对地层变形较敏感的环境。
MJS operating principle: jet grouting, controlled slurry discharge, and in-ground pressure monitoring.
MJS 工法原理示意：喷射注浆、受控排浆与地内压力监测相结合。
MJS operating principle: jet grouting, controlled slurry discharge, and in-ground pressure monitoring. Values shown in the source diagram are illustrative, not a project-wide parameter specification.
Treatment Arrangement and Construction Control
Vertical, horizontal, or inclined treatment can be arranged to suit the target zone and available working space. Treatment extent, pile geometry, cement content, and construction sequence are determined for the specific ground conditions and protection requirements.
Key controls include:
- Jetting parameters and grout delivery.
- Forced slurry-discharge volume and continuity of discharge.
- In-ground pressure and its changes during construction.
- Formed-pile diameter and continuity of the treatment zone.
- Deformation monitoring of adjacent tunnels and the ground surface.
Xinhua River Box Culvert, Jinsha Avenue, Hangzhou
The Xinhua River box-culvert works on Jinsha Avenue, between Yueya Road and Xiasha West, were located at the intersection of the planned road and the existing river. The project combined river-channel improvement with culvert construction above the existing Jiubao East–Xiasha West metro tunnel section.
The culvert passed approximately 2–5 m beneath the riverbed. The clear distance between the uplift-pile toes and the top of the tunnel lining was only about 2.84 m, while overhead high-voltage lines were approximately 8 m above site level. The ground-improvement scheme therefore had to address both restricted overhead working space and protection of the metro tunnel below.
MJS 工法原理示意：喷射注浆、受控排浆与地内压力监测相结合。图中数值为原理示意信息，不作为所有工程统一采用的施工参数。
加固布置与施工控制
根据加固部位和作业空间，可采用竖直、水平或倾斜施工。加固范围、桩体几何尺寸、水泥掺量和施工顺序需结合具体地层条件及邻近设施保护要求确定。
施工控制重点包括：
- 喷射参数与供浆情况。
- 强制排浆量及排浆连续性。
- 地内压力及其施工过程变化。
- 成桩直径和加固区域连续性。
- 邻近隧道及地表变形监测。
杭州金沙大道新华河箱涵工程
杭州金沙大道（月雅路—下沙西）新华河箱涵工程位于规划金沙大道与现状新华河交叉口，是河道整治拓宽工程中的涵洞工程，施工位置处于既有九堡东站—下沙西站地铁区间上方。
箱涵下穿河床约 2–5 m，抗拔桩桩底与隧道管环顶净距仅约 2.84 m；地上高压线距场地标高约 8 m。加固施工既受到上方作业净空限制，也需保护下方既有地铁隧道。
Treatment cross-section showing the relationship between the culvert, ground-improvement zone, and existing metro tunnel.
加固剖面展示箱涵、地基加固范围与既有地铁隧道的位置关系。
Treatment cross-section showing the relationship between the culvert, ground-improvement zone, and existing metro tunnel.
Full-area treatment was carried out using MJS. Cement content was 20% within the box-culvert structural zone and 50% beneath the culvert raft foundation, with different treatment requirements addressed by zone.
加固剖面展示箱涵、地基加固范围与既有地铁隧道的位置关系。
项目采用 MJS 工法进行满堂加固。其中，箱涵结构部位水泥掺量为 20%，箱涵筏板下部水泥掺量为 50%，分区域满足不同部位的地基加固要求。
MJS site arrangement beneath overhead high-voltage lines at the Xinhua River box-culvert project.
新华河箱涵工程现场，高压线下方的 MJS 设备布置与施工环境。
MJS site arrangement beneath overhead high-voltage lines at the Xinhua River box-culvert project.
Construction commenced on March 15, 2024, and was completed on May 15, 2024. The works provided the required foundation treatment under the combined constraints of overhead power lines and the existing shield tunnel below.
新华河箱涵工程现场，高压线下方的 MJS 设备布置与施工环境。
施工于 2024 年 3 月 15 日开始，至 2024 年 5 月 15 日完成，在上方高压线及下方既有盾构隧道的双重约束条件下完成箱涵地基加固。
MJS ground-improvement works in progress. Site photos illustrate equipment arrangement and working conditions.
MJS 地基加固施工过程，展示设备布置和现场作业条件。
MJS ground-improvement works in progress. Site photos illustrate equipment arrangement and working conditions.
The 20% and 50% cement contents and the geometric clearances above relate to this project; they are not universal MJS design or construction parameters.
MJS 地基加固施工过程，展示设备布置和现场作业条件。
上述 20%、50% 水泥掺量及工程净距均为本项目条件，不作为其他 MJS 工程直接套用的设计或施工参数。
Related Products & Solutions
关联产品与解决方案
Automatically selected based on supplier, category, keywords and offering type.
PROFESSIONAL SERVICES
TJS Radial Soil-Cement Pile Reinforcement for Shield Tunnels in Soft Ground
软土地层隧道径向水泥土桩加固技术（TJS工法）
View Details
PROFESSIONAL SERVICES
TRD Equal-Thickness Soil-Cement Wall and TAD Precast Assembled Diaphragm Wall
TRD等厚水泥土连续墙与TAD预制装配式地下连续墙
View Details
PROFESSIONAL SERVICES
IMS Low-Disturbance Soil Mixing Method
IMS微扰动搅拌工法
View Details