Abstract
As a major technical challenge in tunnel construction, thermal hazards induced by geothermal anomalies encompass disaster-causing elements including hot water and gas sources, transport pathways, dynamic mechanisms, and engineering indicators, featuring strong concealment, high suddenness, and complex disaster-causing mechanisms. To identify thermal hazard-inducing structures in tunnels and quantitatively assess their risks, a technical system of "regional geothermal geological background analysis - multi-stage targeted identification at tunnel site - thermal hazard risk assessment" was established. First, recognizing that regional-scale geothermal geological characteristics determine the scale of disaster sources, a regional-scale hazard-inducing structure identification technique was developed based on regional ground temperature field characteristics and geological-geothermal coupling relationships, facilitating the selection of appropriate "low-temperature corridors." Subsequently, acknowledging that tunnel-site-scale hazard-inducing structures determine disaster locations, geological-geothermal collaborative investigation techniques—including geochemical tracing, comprehensive geophysical exploration, and drilling—were proposed for the survey and design stage, along with static thermal hazard risk assessment methods, achieving preliminary identification of thermal convergence characteristics such as tunnel "thermal recharge, thermal sections, and thermal phenomena" and static assessment of thermal risks. Finally, for potential high-temperature sections, multi-phase thermal parameter tracking monitoring techniques and dynamic thermal risk assessment methods were proposed for the construction stage, encompassing borehole rock temperature, hydrochemical characteristics, gas types and concentrations, enabling advanced targeted identification of thermal convergence characteristics such as "thermal degree, thermal scale, and thermal grade" in high ground temperature tunnel sections and dynamic assessment of thermal risks. Additionally, future research trends for thermal hazard identification and risk assessment technologies in geothermal anomaly tunnels were discussed. The research findings provide a novel technical system for thermal hazard prevention and control in tunnels, offering guidance for safe tunnel construction.
Full Text
Preamble
Hazard Structure Identification and Risk Assessment of Thermal Disasters in Deep-Buried Tunnels
ZHANG Shishu, ZHAO Xiaoping
PowerChina Chengdu Engineering Corporation Limited, Chengdu 610031, China
Abstract
Thermal hazards induced by geothermal anomalies represent a major technical challenge in tunnel construction. These hazards encompass sources of hot water and gas, transport pathways, dynamic mechanisms, and engineering precursors, with disaster manifestations characterized by strong concealment, high suddenness, and complex mechanisms. To identify the hazard-inducing structures of tunnel thermal disasters and quantitatively assess their risks, this study establishes a comprehensive technical system comprising "regional geothermal geological background analysis, multi-stage targeted identification at the tunnel site, and thermal hazard risk assessment."
At the regional scale, where geothermal geological characteristics determine the scale of disaster sources, a regional-scale hazard structure identification technique is developed based on regional geothermal field characteristics and geological-geothermal coupling relationships, facilitating the selection of optimal "low-temperature corridors." At the tunnel site scale, where hazard structures determine disaster locations, geological-geothermal collaborative investigation techniques—including geochemical tracing, comprehensive geophysical exploration, and drilling—are proposed for the survey and design phase, together with a static thermal hazard risk assessment method. This enables preliminary identification of thermal convergence characteristics such as "thermal recharge, thermal sections, and thermal phenomena" and static assessment of thermal risks.
For potential sections with high geothermal temperatures during construction, multi-phase thermal parameter tracking monitoring techniques are implemented, encompassing borehole rock temperature, hydrochemical characteristics, gas types and concentrations, along with dynamic thermal risk assessment methods. This achieves advanced targeted identification of thermal convergence characteristics including "thermal degree, thermal scale, and thermal grade" in these sections and enables dynamic assessment of thermal risks. The paper also discusses future research trends in identification and risk assessment technologies for thermal hazards in geothermal anomaly tunnels. The research results provide a novel technical system for the prevention and control of tunnel thermal hazards and offer significant guidance for safe tunnel construction.
Keywords: tunnel engineering; geothermal anomaly zone; thermal hazard; hazard-inducing structure; risk assessment