Engineering Challenges and Solutions in Karst Regions

Introduction

Karst landscapes, formed from soluble rocks like limestone and dolomite, showcase a variety of geological features such as caves, sinkholes, and solution grooves. These unique formations arise through prolonged groundwater erosion and are prevalent in many areas across the globe (Parise et al., 2015). However, constructing in these regions can pose unforeseen risks, including sudden ground collapses that jeopardize both structures and personnel. Therefore, understanding and managing karst features is critical in engineering applications.

Karst Detection

Detecting karst formations is a cornerstone of geotechnical investigations in affected regions. Various methods are employed, including geological mapping, engineering drilling, and geophysical exploration (Li and Xiao, 2006; Goldscheider et al., 2011; Kaufmann, 2014). Among these, geophysical techniques stand out due to their minimal site disruption and broader applicability.

Wang et al. explored four prominent geophysical methods for karst detection: multi-electrode resistivity, cross-hole electromagnetic wave tomography, microtremor surveys, and ground-penetrating radar. Their research revealed that a novel layout for 3D electrical exploration allows for a more efficient detection of karst groundwater channels, improving both exploration efficiency by 85.9% and accuracy compared to conventional methods.

Geological Assessment in Karst Areas

Karst collapses present significant hazards, characterized by sudden surface subsidence and potential destruction of structures. To minimize such risks, it’s imperative to assess and predict these events accurately.

Machine learning has emerged as a transformative tool for predicting potential hazards in various engineering contexts (Qu et al., 2021; Qu et al., 2023). For instance, machine learning models have been developed to predict karst collapses utilizing an optimized sparrow search algorithm in conjunction with extreme learning machines. This adaptive intelligent prediction framework enhances model accuracy and reliability by adjusting weights and using chaotic mapping for improved search capabilities.

Karst Treatment

Addressing the complexities of karst features is essential to prevent engineering mishaps. One prevalent method for treating these formations is grouting, which often faces challenges in high-water-flow environments. Liang et al. addressed these issues by developing a high-performance modified clay-cement grouting material, proving effective in both laboratory tests and field applications.

To combat water inrush and seepage issues at diaphragm wall joints, Jiang et al. proposed a dual approach that combines geophysical exploration with specialized grouting techniques. This involves sealing identified flow channels with clay-cement paste while using sonar for detecting leaks at diaphragm wall joints, subsequently treating these with cement-sodium silicate grouting.

Xu et al. further contributed to this field with a grouting control standard based on catastrophe theory for underwater karst shield tunnels. Their analysis of instability mechanisms led to modeling tools that aid in reinforcing these sensitive structures effectively.

Construction Cases in Karst Formations

The unique challenges presented by karst strata during shield tunneling can lead to severe complications, including machine sinking and excessive settlement (Cheng et al., 2017). The risks can result in profound economic loss and, in extreme cases, casualties (Xie et al., 2025).

One illuminating case study involved a shield tunneling project in Shenzhen, China, where Li et al. introduced a membrane-sleeve valve pipe grouting technique. This innovation aimed to enhance the reinforcement of karst strata, and field tests underscored its practical applicability. Additionally, enhancements to traditional blasting techniques for hard rock tunneling were established by Tu et al., showcasing the adaptive strategies employed in this challenging environment.

Machine learning has also become integral in evaluating geological records alongside tunneling parameters to predict rock grades, reflecting the intersection of technology and geology in modern engineering practices.

Through the contributions of various research teams and professionals, significant advancements are being made to tackle the challenges posed by karst landscapes, paving the way for safer and more efficient construction methodologies.