针对北京地区以细砂、粉质黏土、粉细砂等软土为主且带有微承压性的富水软弱地层，京沈高铁盾构隧道5#和6#联络通道因地面有建筑物无法采取地面加固措施，为防止联络通道在预加固过程中地层沉降或隆起、因地层加固效果不佳在开挖过程中发生涌水涌砂、掌子面垮塌等风险而引起地面建构筑物坍塌破坏,采用MJS工法向下半圆方式进行喷射的超高压水平旋喷桩加固地层，取得了良好的成桩和止水效果，有效提高土体自稳能力、隔断承压水，最大程度减少联络通道地层加固和开挖施工对地面房屋的沉降影响。在MJS加固期间，地表隆起最大值仅为0.93 mm，开挖和衬砌完成后的最大沉降值仅-2.85 mm，满足房屋鉴定评估控制值的要求，保证了地面建筑物的安全。证明在城市内富水的黏土、粉质黏土、粉细砂层中采用水平MJS工法进行水平旋喷桩加固地层效果显著，可以获得良好的社会效益和经济效益。

The ground in Beijing area is mainly composed of waterrich weak soils containing fine sand, silty clay, and silty fine sand. The ground reinforcement cannot be applied to #5 and #6 connection galleries of BeijingShenyang highspeed railway shield tunnel because of buildings on the ground. Hence, to avoid the collapse damage of ground buildings induced by the strata settlement during prereinforcement process, the water and sand gushing due to poor reinforcement effect, and tunnel face collapse, the metro jet system(MJS) method is adopted to consolidate the strata with superhigh pressure horizontal jet grout piles, resulting in good reinforcement effect, which can improve the selfstability and confined water isolating effect of soils and reduce the influence of strata reinforcement and excavation on the settlement of ground buildings to the maximum extent. The results show that the maximum uplift of ground is 0.93 mm, the maximum settlement is -2.85 mm after excavation and lining completion, which meets relevant requirements and guarantees the building safety. The results indicate the prominent ground reinforcement effect of horizontal jet grouting pile by MJS method in waterrich clay, silty clay, and silty fine sand strata in urban areas, which can achieve good social and economical benefits.