Investigation on Hydraulic Fracturing and Flexible Anti-Hydrofracturing Solution for Xiaowan Arch Dam

Abstract

Understanding hydraulic fracturing in concrete super-high arch dams is vital for the implementation of safety measures on the bearing surface. In this study, we conducted tests on hydraulic fracturing for the Xiaowan arch dam (294.5 m) to analyze concrete behavior at cracks under various stress conditions. The risk of hydraulic fracturing near the dam heel was identified without compressive stress. Addressing this, we propose a flexible anti-hydrofracturing system using GB sealing material and a spray polyurea coating. Simulation tests on three schemes: ‘3 mm GB plate + 4 mm polyurea’, ‘1 mm GB glue + 5 mm polyurea’, and ‘7 mm polyurea’ showed effective prevention of hydrofracturing at concrete crack openings of 5 mm, 8 mm, or 10 mm under 300 m water pressure. Field tests supported ‘3 mm GB plate + 4 mm polyurea’ and ‘7 mm polyurea’ as optimal solutions for dam sections. Implementation involves a protective block layout with ‘3 mm GB plate + 4 mm polyurea’ on blocks and ‘7 mm polyurea’ in interval zones and corners. Since 2008, maximum leakage, including rock foundation, has remained minimal at 2.78 L/s under regular water levels. These insights aid similar concrete dams in optimizing safety systems.

A Method for Evaluating Systematic Risk in Dams with Random Field Theory

“…The dislocation zone is mainly composed of crushed rock, breccia, a small amount of mylonite, and fault gouges. Two groups of fissures have developed in the foundation of the dam section, 1 ⃝ N20…”

“…As seen in Figure 3, there are many structural planes due to the complexity of the rock foundation; thus, it is important to determine the critical failure paths. Therefore, the potential failure paths are searched using the load increment method, and seven potential critical failure paths in the dam-foundation system are obtained according to the progressive failure process of elements under step-by-step loading (as shown in Figure 4), in which failure paths 1 ⃝-3 ⃝ are in the dam body and failure paths 4 ⃝-7 ⃝ are in the foundation. For these determined critical failure paths, the performance functions are constructed according to the failure criteria.…”

“…Dams are widely used in the world for irrigation, shipping, power generation, flood control, water supply, etc. The safe operation of dams has long been a great concern for governments and scholars [1,2]. According to the statistics of 142 gravity dam accidents between 1802 and 1998, more than 50% were caused by foundation instability and structure damage [3][4][5][6][7][8], so making sure the long-term safe operation of gravity dams is particularly important.…”

A New Method for Constructing the Protection and Seepage Control Layer for CSGR Dam and Its Application

“…This innovation eliminated the need for an anchorage system, simplifying construction processes. However, the heightened efficiency came at the expense of increased costs [22]. Consequently, there is a need to develop a new type of surface water stop that balances safety, cost-effectiveness, and ease of construction for CSGR dams.…”