Subsidence can result from the collapse of underground cavities. The impact of such subsidence on existing structures and infrastructures is generally dramatic. Geosynthetic reinforcement (GSY) is an attractive mitigation solution that can be used to reduce this impact. This paper focuses on the mitigation solutions over existing cavities mainly on the GSY mitigation method. A large-scale physical model (1-g) is used to study the subsidence mechanisms and to estimate the efficacy of GSY for both cohesive and granular overlying soils. The results show that the presence of GSY reduces the ground movement due to the cavity progress toward surface, even under significant overload (traffic, localised foundation, etc.). The deformation of the GSY and the scenario for ground surface movement (subsidence or sinkhole) depend on both the soil type and overload intensity. The experimental results are compared to the analytical solutions proposed to design the GSY for cohesive and granular soils. In particular, the influence of the vertical stress distribution acting on the GSY is investigated. Different geometries of stress distribution are proposed for granular soils as a function of the loading mode (self-weight or localised overload). For cohesive soils, the action of the collapsed soil on the GSY sheet is found to be well estimated by considering the effect of a simplified system composed of two well localised punctual forces. The analytical and experimental results obtained are rather similar, proving the relevance of the analytical models in predicting the behaviour of reinforced soil layers taking into consideration the real stress distribution deduced from the experimental results.

地下空腔的塌陷可能导致沉降。这种沉降对现有结构和基础设施的影响通常是巨大的。土工合成材料加固（GSY）是一种有吸引力的缓解解决方案，可用于减少这种影响。本文主要针对GSY缓解方法，研究现有型腔的缓解解决方案。使用大型物理模型（1-g）研究沉降机理并评估GSY对粘性和颗粒状覆土的有效性。结果表明，即使在明显的超载（交通，局部地基等）下，由于空腔朝向地面前进，GSY的存在也会减少地面运动。GSY的变形和地表运动（沉降或下陷）的情况取决于土壤类型和过载强度。将实验结果与为粘性和粒状土壤设计GSY的分析解决方案进行了比较。特别是，研究了垂直应力分布对GSY的影响。对于粒状土壤，提出了根据加载模式（自重或局部过载）而不同的应力分布几何形状。对于粘性土，考虑到由两个良好定位的点扎力组成的简化系统的作用，可以很好地估计塌陷土在GSY板上的作用。获得的分析和实验结果相当相似，