为解决在南昌富水条件下砂层与泥质粉砂岩复合地层中喷涌、结“泥饼”、渣土“流塑性差、含水量高、渗透系数大”等施工难点，以南昌地铁1号线中子（中山西路站—子固路站）区间、八八（八一广场站—八一馆站）区间盾构施工为背景，通过数据统计及案例分析，得出液态高分子聚合物可作为抑制喷涌常态措施，泥质粉砂岩及富水砾砂层地质条件下，选取泡沫剂作为渣土改良添加剂，在砂砾石与泥质粉砂岩的复合地层，可考虑添加一定量的膨润土或高分子聚合物，解决砂砾石地层中渣土流动性差、防喷涌及粉质泥沙岩中结“泥饼”等问题。砂砾层体积与渣土总体积之比小于等于1/3时，渣土改良方式采用泡沫剂与分散剂溶液；大于1/3而小于2/3时，改良方式采用膨润土与泡沫剂溶液；大于等于2/3时，改良方式采用水土比8∶〖KG-*2/3〗1膨润土与浓度为3%泡沫剂溶液，但膨润土用量应增加。

During shield tunneling in the composite strata consisting waterrich sand and silty sandstone in Nanchang, difficulties such as water/muck gushing, muck blocking, poor muck plasticity, waterrich muck and highlypermeable muck may be faced. In the paper, the ground conditioning applied in the construction of ZhongZi running tunnel and BaBa running tunnel on Line 1 of Nanchang Metro is studied. Conclusions drawn are as follows: 1) Liquid highmolecular polymer may be taken as the common measure to control the water/muck gushing; Foam may be taken as the ground conditioning agent in silty sandstone geology and waterrich gravel sand strata; 2) In the composite ground consisting of sand gravel and silty sandstone, some bentonite or highmolecular polymer may be added so as to solve such problems as low fluidity of mucks, water/muck gushing and muck blocking; 3) Where the volume of the sand gravel is not more than 1/3 of the total volume of the mucks, foam and dispersing solution may be used for grounding conditioning; Where the volume of the sand gravel ranges from 1/3 to 2/3 of the total volume of the mucks, bentonite and foam solution may be used for grounding conditioning; Where the volume of the sand gravel is equal to or larger than 2/3 of the total volume of the mucks, bentonite solution (with the waterbentonite ratio being 8∶〖KG-*2/3〗1) and foam solution (with the foam concentration being 3%) may be used for grounding conditioning, and the consumption of bentonite shall be increased. 