Predictive modeling of lateral pressure in geotextile flexible casings for karst pile construction

In modern geotechnical engineering, geotextile-integrated flexible casings have gained prominence over conventional steel counterparts for concrete containment in karst pile construction, primarily due to their economic advantages and operational simplicity. However, the dynamic behavior of casing lateral pressure development during concrete placement—a fundamental design consideration—has not been thoroughly elucidated, creating uncertainties in engineering practice. This study systematically investigates three key operational parameters through laboratory experiments: casing material characteristics, permeability performance, and concrete placement methods. The research yields two critical advancements: (1) Casing material and discontinuous casting significantly govern the maximum lateral pressure, whereas permeability predominantly regulates post-placement pressure dissipation patterns. Engineering specifications should therefore emphasize the integration of low-strain geotextiles with permeability characteristics and discontinuous placement methods. (2) An innovative predictive model has been developed, synthesizing material properties, permeability performance, and concrete placement methods. Field tests in a karst region show that the proposed model reduces lateral pressure estimates by 42 % compared to traditional hydrostatic designs while maintaining structural safety. These findings establish essential guidelines for performance-oriented design of flexible geotextile containment systems in geologically complex environments.