我国薄煤层资源分布较为广泛，储量丰富。实现高效开采是薄煤层开采面临的重要课题，柔模混凝土沿空留巷技术为提高薄煤层煤炭回收率、降低巷道掘进率、高效开采提供了解决途径。本文采用理论分析、数值模拟、现场实测和工业性试验相结合的方法，开展了柠条塔煤矿 N1215 薄煤层工作面柔模混凝土沿空留巷技术及应用研究，主要研究结果如下：

（1）研究了沿空留巷上覆岩层垮落规律和围岩应力分布规律，得出沿空留巷顶板活动前期和过渡期对沿空留巷巷旁支护的影响最大。沿空留巷期间，巷道围岩应力分布为应力降低区、应力增高区、应力稳定区；留巷复用期间，围岩应力分布主要分为应力降低区、应力叠加区、应力稳定区、原岩应力区。

（2）优化了柠条塔煤矿 N1215 薄煤层工作面的支护方案，使巷道在不同工况下整体支护强度可满足巷道使用要求。确定了初期柔模混凝土留巷巷旁支护体宽度为 1.0m，混凝土强度设计为 C40。

（3）巷旁支护设计选择将柔模墙体浇筑于采空区，浇筑墙体宽度1.0m，高度随工作面采高而定，混凝土强度 C40，保留运输巷宽度 5.1m；临时加强支护中超前支护不变，滞后支护选择“一梁四柱”进行支护。

（4）结合工程实践，确定了沿空留巷支护方案。将柔模混凝土墙体浇筑于采空区，留巷墙体厚度 1.0m，强度 C40，巷道宽度 5.1m。实践表明，巷道变形总体上表现为：顶板下沉量＞底板底鼓量＞主帮移近量＞副帮移近量；在距工作面滞后 80m 范围内巷道变形最为剧烈，巷道压力显现较为明显，基本上在滞后工作面 130m 后趋于稳定。

柔模混凝土沿空留巷技术在柠条塔煤矿 N1215 薄煤层工作面获得成功应用，节省区段煤柱并减少掘巷创造直接经济效益 1.06 亿元，取得了良好效果。

China's thin coal seam resources are widely distributed and have abundant reserves. Realizing efficient mining is an important issue faced by thin coal seam mining. The flexible formwork concrete goaf retaining technology provides a solution to improve the coal recovery rate of thin coal seams, reduce tunnel excavation rate, and achieve efficient mining. This article adopts a combination of theoretical analysis, numerical simulation, filed research and industrial experiments to study the technology and application of flexible formwork concrete roadway retention along the goaf in the N1215 thin coal seam working face of Ningtiaota Coal Mine. The main research content and results are as follows:

(1) The collapse law of the overlying strata and the distribution law of surrounding rock stress in the goaf retaining roadway were studied, and it was found that the early and transitional stages of the roof activity in the goaf retaining roadway have the greatest impact on the side support of the goaf retaining roadway. During the period of goaf retention, the stress distribution of the surrounding rock of the roadway is divided into stress weakening zone, stress rising zone, and stress stable zone. During the reuse period of retaining tunnels, the stress distribution of surrounding rocks is mainly divided into stress reduction zone, stress superposition zone, stress stability zone, and original rock stress zone.

(2) The support plan for the N1215 thin coal seam working face of Ningtiaota Coal Mine has been optimized, so that the overall support strength of the tunnel can meet the requirements of tunnel use under different working conditions. It has been determined that the width of the support body for the initial flexible formwork concrete retaining roadway is 1.0m, and C40 concrete strength design is adopted.

(3) During the industrial experiment, the design of roadside support chose to pour the flexible formwork wall into the goaf, with a width of 1.0m and a height depending on theheight of the working face. The concrete strength was C40, and the width of the transportation roadway was retained at 5.1m. In the temporary strengthening support, the forward support remains unchanged, while the backward support is selected as "one beam and four columns" for support. 

(4) Based on engineering practice, the design of roadside support chose to pour the flexible formwork wall into the goaf, with a thickness of 1.0m, a strength of C30, and a width of 5.1m. Practice has shown that the overall deformation of the roadway is as follows: roof subsidence>floor heave>main wall displacement > auxiliary wall displacement. The deformation of the roadway is most severe within the range of 80m behind the working face, and the pressure of the roadway is more obvious. Basically, the roadway tends to stabilize after 130m behind the mining face. 

The flexible formwork concrete goaf retaining technology has been successfully applied in the N1215 thin coal seam working face, saving section coal pillars and reducing the economic benefits created by tunneling by 106 million yuan, achieving good results.