Rock Caverns Research Articles

Rainwater catchment and the challenges of sustainable development

Early mankind impounded rainfall in rock caverns for consumptive needs. The first farmers situated plots below slopes where runoff could be diverted. Rainwater catchment was an early step in pursuit of sustenance. What is ancient in one respect, however, remains new in another. Rainwater catchment is today employed worldwide for potable and agricultural water supply. Technology is advancing in roofing, guttering and storage, water quality protection and distribution. Catchments abound in both developing and economically advanced nations. Applications include both adaptations to traditional dwellings and modern architecture. Fundamentally more changed than new technology or applications, however, is the viewpoint from which rainwater catchment can be evaluated. Rainwater catchment is a systems problem, a collection of interactive components best understood not as parts, but in their interrelationship. So viewed, rainwater catchment merits consideration as a component of sustainable water resource development. This paper reviews the challenges of rainwater catchment in sustainable development.

Phenology and ecology of hibernation in spotted turtles (Clemmys guttata) near the northern limit of their range

Using mark-recapture techniques, temperature-sensitive radio transmitters, and miniature temperature data loggers we investigated the hibernation ecology of northern temperate zone spotted turtles (Clemmys guttata) in Georgian Bay, Ontario, over 4 winters (1993-1997). We observed 18 hibernacula that were occupied by 34 turtles; 11 hibernacula were apparently occupied by single turtles, and 7 were used communally by up to 9 individuals. Hibernacula were located in swamps and were of 2 types: sphagnum moss hummock (n = 15) and rock cavern (n = 3). Almost half of the individuals (16 of 34) used the same hibernaculum in at least 2 winters. Turtles entered hibernacula between mid-September and October, when their body temperature was between 12 and 16°C, and exited them in mid to late April, when ambient temperatures ranged between 1 and 5°C. A waterproof temperature data logger attached to a turtle indicated that this turtle was protected from freezing in a thermally stable hibernaculum (body temperature range 0.3-3.9°C) despite highly variable (a 37°C change over 5 days) and low air temperatures (minimum -35°C). Loss of body mass (2%) during hibernation was not significant. We observed no mortality within hibernacula over the 4 winters; however, 3 turtles were destroyed by predators near the hibernacula. These data provide insight into the role of climate in limiting the northern distribution of this species.

Underground cavern development in the Jurong sedimentary rock formation

The Jurong Formation forms the west and southwest of the Singapore Island. The formation consists of sedimentary rocks of late Triassic to early Jurassic age. The rocks include various types of mudstone, sandstone, shale, conglomerate, phyllite, slate and limestone. They have been intensely folded with their structural strike generally oriented NW-SE and faulted with the faults generally aligned parallel with or perpendicular to the fold strike. The Jurong Formation has been studied for the potential development of rock caverns. Extensive investigations including geological mapping, seismic reflection surveys, and deep coring have been conducted. This paper presents some of the results from the investigations and discusses the potential of cavern development in the Jurong Formation.

Modeling stress-dependent permeability for anisotropic fractured porous rocks

Most of deep geological engineered structures, such as rock caverns, nuclear waste disposal repositories, metro rail tunnels, multi-layer underground parking, are constructed within hard crystalline rocks because of their high quality and low matrix permeability. In such rocks, fluid flows mainly through fractures. Quantification of fractures along with the behavior of the fluid flow through them, at different scales, becomes quite important. Earlier studies have revealed the influence of sample size on the confining stress–permeability relationship and it has been demonstrated that permeability of the fractured rock mass decreases with an increase in sample size. However, most of the researchers have employed numerical simulations to model fluid flow through the fracture/fracture network, or laboratory investigations on intact rock samples with diameter ranging between 38 mm and 45 cm and the diameter-to-length ratio of 1:2 using different experimental methods. Also, the confining stress, σ3, has been considered to be less than 30 MPa and the effect of fracture roughness has been ignored. In the present study, an extension of the previous studies on “laboratory simulation of flow through single fractured granite” was conducted, in which consistent fluid flow experiments were performed on cylindrical samples of granitoids of two different sizes (38 mm and 54 mm in diameters), containing a “rough walled single fracture”. These experiments were performed under varied confining pressure (σ3 = 5–40 MPa), fluid pressure (fp ≤ 25 MPa), and fracture roughness. The results indicate that a nonlinear relationship exists between the discharge, Q, and the effective confining pressure, σeff., and Q decreases with an increase in σeff.. Also, the effects of sample size and fracture roughness do not persist when σeff. ≥ 20 MPa. It is expected that such a study will be quite useful in correlating and extrapolating the laboratory scale investigations to in-situ scale and further improving theoretical/numerical models associated with fluid flow through rock masses.

Finite element analysis of a pilot gas storage in rock cavern under high pressure

A three-dimensional finite element analysis was performed to simulate field tests at a pilot gas storage project. The storage was a shallow rock cavern lined with a 6 mm thick steel liner. During the tests, high internal pressure up to 52 MPa was applied and deformation of both rock mass and the steel liner was recorded. The maximum rock displacements of less than 6 mm was numerically predicted and fits the measurement very well. The three-dimensional nonlinear finite element modeling has confirmed the overall stability of the structure and revealed the functioning of each structural component, including the rock mass, concrete lining and the steel liner.

Micromechanical analysis on deterioration due to freezing and thawing in porous brittle materials

A porous brittle material such as concrete or rock deteriorates when subjected to freezing and thawing. Based on a hypothesis that the cause of the deterioration is the fracture of micropores due to water freezing and moving in them, a micromechanical model is constructed for these microscopic processes and an analysis method of predicting the deterioration degree is developed. The validity of the deterioration analysis is examined by conducting numerical simulation for experiments which were carried out in various conditions. It is shown that the analysis can reproduce the measured data quantitatively. Since the temperature and local stress influence the deterioration process, an FEM is formulated for the deterioration analysis; this is coupled with the heat transfer and mechanical deformation analysis. As an example, the deterioration is analyzed for a rock cavern which stores LNG. The results appear in good agreement with the qualitative prediction of experts.

原位置ＡＥ計測に基づいた岩盤ゆるみ域の評価

When constructing large underground caverns such as hydraulic power stations and oil storages, it is important to estimate the loosened area around rock caverns caused by excavation. If the loosened area around a rock cavern is known, the most suitable support members and quantities can be determined. The authors have carried out in situ experiment to investigate the crack growth into rock mass by acoustic emission (AE) measurement.In this paper, parameter analysis, locational analysis and moment tensor analysis based on the observed AE signal waves were carried out to make clear the diffusing patterns, locations, orientations and crack types of AE sources. The following conclusions were obtained: (1) Many large amplitude AE signal waves diffused within about ten minutes after cavern blasting, (2) The concentrated areas of tensile cracks and shear cracks around a rock cavern were different, (3) From the distribution of observed AE signal waves, the loosened area was estimated within depth of 2m from the excavated wall.

岩盤の「割れ目」に対応した水封評価法

The first rock caverns for oil storage in Japan have been constructed in Kuji, Kikuma and Kushikino. Although many phenomena could not maintain the necessary ground water level through some cracks and fractures which occurred during the process of actually constructing the rock caverns, we were able to complete the storage facilities into service by the various measures to render water-sealing effective. As a result, it was confirmed that the observation of the flow trends through water passage is most important to secure the water-sealing system. For this reason, we made the classification and evaluation system to be composed mainly of "Evaluating Water Passages" and "Geological Conditions such as Joint Spacing etc.", how to evaluate jointed rock masses with respect to water-sealing. This paper describes the outline of such classification for aiming and helping the development of water-sealing technology.

The First Rock Cavern for LPG in Japan Its Technical Basis

The First Rock Cavern for LPG in Japan Its Technical Basis

A proposition and application of efficient excavation system on the large rock cavern

A proposition and application of efficient excavation system on the large rock cavern

High-definition in-situ stress measurements in tunneling

There are two principal objectives of in-situ stress measurements in tunneling: ⊙ For the design of the tunnel support system: Evaluation of the primary (geologic) state of stress, usually carried out prior to the tunnel excavation and ⊙ for proof of the stress redistribution processes and the extent of the “Plastic Zone” around the tunnel: Evaluation of the secondary state of stress, usually carried out as a part of a tunnel monitoring programme. By definition, stress measurements are measurements at a point. Considering the highly inhomogeneous nature of rock a high degree of scatter of stress data is quite common. However, the most commonly used stress measuring methods (i.e. the overcoring methods) are not designed for carrying out a large number of measurements, as they are expensive and technically cumbersome. With the increased acceptance of alternative non-overcoring methods such as borehole slotting and hydraulic fracturing, the relevance of in-situ stress measurements has increased in recent years significantly. Examples of high-definition borehole slotting tests are presented from various regions of Central Europe which include the Ruhr destrict (deep coal mining), the Thuringian Forest (rock cavern) and the Alps (railway base tunnels). The examples are indicative of the new class of reliability with which both primary and secondary stress state around tunnels can be determined.

Design and construction aspects of unlined oil storage caverns in rock: Y. N. Lee, S. P. Yun, D. Y. Kim & H. K. Nam, Tunnelling & Underground Space Technology, 11(1), 1996, pp 33–37

Design and construction aspects of unlined oil storage caverns in rock: Y. N. Lee, S. P. Yun, D. Y. Kim & H. K. Nam, Tunnelling & Underground Space Technology, 11(1), 1996, pp 33–37

Construction and utilization of rock caverns in Singapore. Part D: planning and location selection: J. Zhao & K. W. Lee, Tunnelling & Underground Space Technology, 11(1), 1996, pp 81–84

Construction and utilization of rock caverns in Singapore. Part D: planning and location selection: J. Zhao & K. W. Lee, Tunnelling & Underground Space Technology, 11(1), 1996, pp 81–84

Construction and utilization of rock caverns in Singapore. Part A: the Bukit Timah granite bedrock resource: J. Zhao, Tunnelling & Underground Space Technology, 11(1), 1996, pp 65–72

Construction and utilization of rock caverns in Singapore. Part A: the Bukit Timah granite bedrock resource: J. Zhao, Tunnelling & Underground Space Technology, 11(1), 1996, pp 65–72

Construction and utilization of rock caverns in Singapore. Part D: two proposed cavern schemes: J. Zhao & J. Bergh-Christensen, Tunnelling & Underground Space Technology, 11(1), 1996, pp 85–91

Construction and utilization of rock caverns in Singapore. Part D: two proposed cavern schemes: J. Zhao & J. Bergh-Christensen, Tunnelling & Underground Space Technology, 11(1), 1996, pp 85–91

Plan and survey of an underground art museum in Japan, using a large-scale rock cavern

The Takayama Festival Float Art Museum, which is located in Takayama City in the Hida District of Gifu Prefecture, in central Japan, is the first large-scale rock cavern for public use in Japan. This paper outlines the project rationale, structural design, and construction of the museum.

Support of large rock caverns in Norway: E. Broch, A. M. Myrbang & G. Stjern, Tunnelling & Underground Space Technology, 11(1), 1996, pp 11–19

Support of large rock caverns in Norway: E. Broch, A. M. Myrbang & G. Stjern, Tunnelling & Underground Space Technology, 11(1), 1996, pp 11–19

Construction and utilization of rock caverns in Singapore. Part B: development costs and utilization: J. Zhao, V. Chao & B. B. Broms, Tunnelling & Underground Space Technology, 11(1), 1996, pp 73–79

Construction and utilization of rock caverns in Singapore. Part B: development costs and utilization: J. Zhao, V. Chao & B. B. Broms, Tunnelling & Underground Space Technology, 11(1), 1996, pp 73–79

An excavation method for large vertical cylindrical caverns

Construction of underground storage chambers in rock has traditionally adopted a construction-oriented approach; the cavern design and the method of excavation have been governed by the capabilities of the equipment available. One example is oil storage in unlined horizontal caverns. Today, however, equipment is no longer a limiting factor. The time has come to integrate the construction and operational aspects in the design process. This paper presents a construction concept developed for large vertical rock caverns with a circular or elliptical horizontal cross-section. The method of excavation, called PBM (Pillar Blasting Method), is condensed into a few main operations which are geometrically separated but overlapping in time. PBM is characterized by two main working sites per cavern, and by long-hole bench-drilling, massive blasting rounds, continuous loading and easy ventilation. Recent developments in drilling and blasting techniques are incorporated, such as the water-driven in-the-hole hammer and the electronic ignition system. PBM enables a high rate of excavation and provides a satisfactory working environment with respect to labour safety and human health (a limited exposure to large openings, no exposure to oil mist and to combustion and explosive fumes, etc). Considerable construction cost savings and time savings may thus be achieved compared to conventional methods of excavation for vertical and horizontal caverns of equal storage volume. A preliminary PCT patent (application No PCT/SE95/00324) has been granted. Examples of applications are fresh-water reservoirs, natural gas reservoirs, subsurface hydroelectric pump power plants, and similar objects which require a large underground storage space in preferably unlined rock caverns.

Design and construction aspects of unlined oil storage caverns in rock

An underground oil storage facility comprising six storage caverns is under construction in southern Korea. Each of the horseshoe-shaped caverns is 18 m wide, 30 m high, and 400–600 m long. The artificial water curtain system used consisted of water curtain tunnels and horizontal boreholes drilled from these tunnels, and pre-grouting measures have been introduced to keep the bedrock saturated all the time in order prevent oil from migrating through rock mass. The results of site investigation show that the bedrock at the site was very competent and impermeable and, hence, a suitable medium for the storage of oil. This conclusion was confirmed later by the results of design analysis, the revised instrumentation program, and hydraulic tests performed during construction. In general, design concepts for the excavation and support and water curtain system have been verified to be reasonably good in terms of the technical soundness and economy. The results of the revised instrumentation program indicate that the three-dimensional excavation behaviour is complex and should be studied in more detail.