Cave temples, as an important type of immovable cultural heritage, are the concentrated manifestation of China's brilliant ancient civilization and a historical testimony of exchanges and mutual understanding between Chinese civilization and other ancient civilizations, but they have been subjected to long-term water erosion and damage, with fissure seepage having a particularly serious impact. For the detection, prevention and control technology of fissure seepage in cave temples in the humid areas of southern China, this paper systematically combs through the research progress in fissure seepage detection technology, fissure seepage disease mechanism, fissure seepage management and control technology, monitoring and assessment technology of management effect, and the demonstration and application of the management technology, with a view to providing references to the relevant researches and work.

To study the performance of sandstone under dry-wet cycles, standard cylindrical specimens were prepared from the sandstone of Nankan Grottoes, and indoor dry-wet cycle tests were designed based on the environmental conditions of the grotto area, through comparing the degradation patterns, quality losses, mechanical parameters, and changes in solution ions of rock masses under different cycles, as well as the mineral composition, element content, cementation characteristics, and particle size changes of the samples before and after cycling. The research results indicate that the hydration and decomposition of feldspar minerals in rocks before and after weathering lead to a decrease in their content and an increase in the content of clay minerals. The rapid loss of major cementing elements such as Fe, Ca and Mg inside the rock, leads to the loss of cementing fluid between particles and damage and fracture of the microstructure of the rock mass, resulting in local mineral disintegration; As the number of cycles increases, the compressive strength and shear strength of the rock gradually decrease, and the cohesive force C between particles decreases linearly with the number of cycles, with little effect on the internal friction angle Φ between particles. The dry-wet cycle mainly causes the loss of coarser particles on the rock surface, while the content of clay particles is relatively reduced, resulting in a more concentrated range of particle sizes on the rock surface.

Most cave temples in China are hosted in sandstone cliffs, which are susceptible to various weathering-induced deteriorations under environmental influences. Among these, surface pulverizing and exfoliation are particularly prevalent, characterized by their extensive distribution and severe impact on the historical and artistic value of sandstone cultural heritage. Feasible and effective consolidation techniques are urgently required to address these issues. Taking the surface pulverizing exfoliation disease at the North Grotto Temple of Qingyang as an example, three reinforcement methods were tested based on the morphological features of the deteriorated surfaces, including spraying, emulsion adsorption and drip infiltration. Through systematic experiments, critical parameters for spraying reinforcement were identified, and the efficacy of solute materials in emulsion adsorption was validated. The results of three methods for reinforcing sandstones of the North Grotto Temple were also evaluated by various qualitative and quantitative analyses.The study clarified the adaptability of these techniques to surface pulverizing exfoliation disease on different sandstone grotto temples, argued that spraying functioned as the foundational method, combined with emulsion adsorption and drip infiltration to meet diverse consolidation requirements. It provides practical insights and methodologies for refining anti-weathering reinforcement technologies and evaluating their effectiveness in cave temple conservation.

The structural instability of grottoes and stone heritage buildings is mostly attributed to the decline in mechanical properties and stability of their key load-bearing components under long-term weathering effects. The stability and the evolution process of instability of these structures are closely related to the stress conditions of the key load-bearing components and the deterioration patterns of their mechanical properties due to weathering. Based on a comprehensive review of the research status on the main problems involved in the stability and durability studies of such grottoes and ancient stone architectures (including the weathering depth of stone components and the determination method of mechanical parameters of weathering layer, the variation law of mechanical parameters with depth in weathering layer, the variation law of weathering depth with time, the evaluation method of stability and durability, etc.), this paper systematically explores potential solutions to address these key scientific and technical challenges. Solutions to the aforementioned problems are briefly introduced through a case study of the stability and durability of the Guyue Bridge in Yiwu built in the Song Dynasty. The methods presented in this article have reference significance for the research on the stability and durability of grottoes and ancient stone architectures.

Water leakage has been the primary problem for the protection of Dazu Rock Carvings (DRC) along with its whole lifetime, but the effect of leakage treatment was far inferior to the demand of protection in the past few decades. Based on conventional hydrogeological theories, this study has carried out by focusing on the Grottoes Cliff Hydrogeology and the special hydrogeological conditions of the unloading cliffs in the Dafowan have been clarified basically. The research shows: Both the sandstone and mudstone of the Dafowan cliff can be regarded as relatively impermeable materials in seepage flow. The bedding planes and tectonic fractures affected by unloading forces constitute the main seepage flow channels within the DRC cliff zone. Some fractures with ten centimeters aperture may form by horizontal landsides along the strata except unloading force. The strata formation of Baodingshan is nearly horizontal, but the EW and SN trending wide-flat folds by tectonic movements of Sichuan and North China periods are very important for the seepage of unloading and unsaturated cliff zones. Water sample analysis from the research area reveals: A complex flow system with long-range and short-range seepage are coexisting within the same space. Geological rock-water interaction and human effects combine along the flow path in the particular cultural cliff rockmass. The flow and material inside water indirectly control derived diseases such as dissolution and salt precipitation. Based on the water level distribution analysis, the hill behind the carving cliff affected by unloading force can be divided into three zones. The non-unloading effect zone is greater than 2 times height of the cliff. The unloading influence zone is 1-2 times the height, and the strong unloading zone is within 1 time the height range. The non-unloading effect zone is dominated by pore saturated flow in the loose soil layer and weathered fractured layer, while the strong unloading zone is dominated by unsaturated and multi-layered fissure flows. The role of opening fractures with high penetration ability must be contemplated dialectically, the leakage water diseases can be aggregated inside these fractures and the seepage flow will be alleviated around these fractures at the same time. The main underground stream flow systems, with complicated mutual crossing flow and leakage recharge inside different flow, have been analyzed. Through this study, a theoretical basis is provided for the systematic and minimal intervention of water seepage treatment in Dafowan, and an example is provided for constructing micro hydrogeological condition models under the special terrain, landform, and environment of cliffs with cultural grottoes and carvings.