[论文解读] Excavation of a 69-m diameter and 94-m high cavern for the Hyper-Kamiokande detector

Y. Asaoka, H. Tanaka+15 more|arXiv (Cornell University)|Feb 16, 2026

Grouting, Rheology, and Soil Mechanics被引用 0

一句话总结

本文记录了 Hyper-Kamiokande 洞穴的设计与施工过程，该洞穴为直径 69 m、高度 94 m 的地下岩石洞穴，埋深约 600 m，采用信息化观测设计并结合 3D 弹塑性稳定性分析来制定支护方案。文中详细描述了开挖序列、地质勘探和建模与现场测量的结合，以确保安全性与成本效益。

ABSTRACT

The excavation of the Hyper-Kamiokande cavern, 600 m underground, is complete. Measuring 69 m in diameter and 94 m in height, it is among the world's largest rock caverns. A vertically oriented, dome-capped cylindrical design was chosen to optimize cost and performance. Combined with substantial overburden, the geometry posed major engineering challenges. This paper outlines the underground works, main cavern design, excavation plan, and the evolution of support design and construction methods during excavation, namely the information-based (observational) design and construction approach.

研究动机与目标

• Explain the underground works and cavern geometry chosen for Hyper-Kamiokande to maximize fiducial mass while maintaining stability under large overburden.
• Describe the geological investigations, initial stresses, and rock-mass properties used to inform the design.
• Present the information-based design and construction approach that integrates 3D analyses with field measurements to guide updates.
• Document the final excavation sequence, support systems, and validation against observed deformations.
• Highlight lessons for future large underground physics caverns and their design-process traceability.

提出的方法

• Use a vertically oriented, dome-capped cylindrical cavern design to optimize cost and performance under ~600 m overburden.
• Apply full 3D sequential elasto-plastic analyses with FLAC3D (v7) to simulate plastic (loosened) zones during sequential excavation.
• Represent geology with a simplified analytical model including planar weak layers and rock-mass classes, calibrated by in-situ tests and measurements.
• Incorporate an information-based (observational) design and construction loop that updates the model and design using ongoing field data.
• Validate predictions by comparing modeled plastic zones and displacements with instrument data collected during excavation.
• Evaluate the effect of pre-tensioned rock anchors (PS anchors) on stabilization within the predicted plastic zones.

Figure 1: (Left) Wide-angle photograph of the completed HK main cavern, showing the entire dome from the bottom of the cylindrical section. The HK cavern is located approximately 600 m underground in the mountains of Kamioka Town, Hida City, Gifu Prefecture, Japan. It has a diameter of 69 m, a heigh

实验结果

研究问题

• RQ1 How can a 69 m diameter, 94 m high cavern be safely excavated with ~600 m of overburden while maintaining cost efficiency?
• RQ2 What are the key geological features and rock-mass properties that govern stability for the HK cavern?
• RQ3 Can an information-based design approach reliably guide excavation sequencing and support design in real time?
• RQ4 How well do 3D elasto-plastic analyses predict the development of loosened zones and displacements during excavation?
• RQ5 What is the role and effectiveness of prestressed anchors in controlling instability in such a large cavern?

主要发现

• The dome's stability is dominated by tensile-type loosening, while the cylindrical section shows shear-dominated behavior.
• 3D sequential elastoplastic analyses, calibrated with on-site measurements, successfully reproduced observed deformation patterns and guided supports.
• PS anchors and shotcrete provided stability in the predicted loosened zones, with pretension showing limited suppression effect under the chosen values.
• The information-based design approach enabled traceable updates from geology and observations to design decisions, supporting cost and schedule optimization.
• The HK cavern achieved a large-span, high-height excavation with robust overburden, illustrating the feasibility of similar future large caverns for particle-physics detectors.

Figure 2: Cross-section of the Hyper-Kamiokande stainless-steel water tank installed inside the 69 m-diameter cavern. The tank is 68 m in diameter and 72 m in height and will be filled with ultra-pure water to 71 m (total 258,000 m 3 ; fiducial 188,000 m 3 ). The detector is partitioned into an Inne