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Theodore Thompson
Theodore Thompson

Practical Tunnel Construction

1IntroductionAlong the trajectory in mechanized tunnelling there are many spatial geological sudden changes in the surroundings that may not be detected in the initial geological surveys. To tackle...

Practical tunnel construction

Practical Tunnel Construction fills a void in the literature for a practical guide to tunnel construction. By taking the reader through a brief introduction and history to a comprehensive discussion of how the geological factors affect tunneling, the author covers the stages and technology that are common today without using complex equations. Written for the individual who does not have an extensive background in tunneling but who has to make tunneling decisions, the various tunneling methods are discussed to help in the determination of the appropriate method. The methods discussed are: hand mining, drill/blast, Tunnel Boring Machine (TBM), New Austrian Tunnelling Method (NATM), Norwegian Method of Tunnelling (NMT), Roadheader, Earth Pressure Balance Machine (EPBM), and Slurry Pressure Balance Machine (SPBM). This book focuses on driven tunnels.

Practical Tunnel Construction is an important resource for students, construction managers, tunnel designers, municipal engineers, or engineers who are employed by government agencies or corporations that are exploring the feasibility of planning and designing or building a tunnel.

GARY B. HEMPHILL, PhD, PE, has more than thirty years of experience in the domestic and international construction industry. He has served as the project manager, designer, estimator, construction manager, field engineer, tunnel/shaft engineer, and project engineer on major projects throughout the world, including the Dallas Area Rapid Transit rail extension and the Taiwan High Speed Rail Project. He is the author of Blasting Operations.

This is arguably the most comprehensive contemporary book on the subject available. Dr. Richemond-Barak conducts a survey of underground warfare, including an in-depth look at the increased use of tunnels around the world, from the strategic to the tactical levels. With a heavy dose of legal analysis she easily revels that there are major gaps in the laws and views towards what lays below all land conflict.

Tunnels were used heavily by the North Vietnamese Army and Viet Cong during the Vietnam War. They were used to protected supply routes, hospitals, and command posts, to house troops, to launch surprise attacks, and much more. One of the most extensive and well-known tunnel complexes were those of the Cu Chi province northwest of Saigon. The Cu Chi tunnels linked Viet Cong support bases over a distance of 250 kilometers, from the outskirts of Saigon all the way to the Cambodian border.

It is important to understand how and where tunnels have been used in warfare. But it is also vital to understand when an environment is ideal for tunnels to be heavily used. What are the geo-technical considerations? What type of equipment and materials are needed? What are the signs of an enemy investing in the capability? Just how, exactly, are tunnels dug? Based on the soil conditions, how long would it take to dig in that environment? What are the required safety considerations? This book is a valuable tool to help understand these questions.

Hydrogen sulfide (H2S) is a toxic gas, and considerable research has been conducted for its control and removal from industrial wastewater and sewage water. However, no simple and practical technology is available for degrading H2S in situ at tunnel constructing sites. On May 11, 2020, an H2S blowout accident occurred in underground soil at a residential sewer-tunnel construction site in Iwakuni City, Yamaguchi Prefecture, Japan, filling the tunnel with high concentrations of H2S gas, causing the fatality of one worker owing to emphysema. River water flowing near the site was immediately introduced into the tunnel to trap the H2S gas, generating 652-m3 water that contained high concentrations (120 mg/L) of dissolved H2S in the tunnel. To safely and quickly remove H2S in situ, the contaminated water was treated with high-density oxygen and ozone nanobubbles (O2/O3-HDNBs) generated using the ultrafine pore method. Consequently, H2S was removed from the contaminated water in 3 days. This is the first successful application of O2/O3-HDNB technology for the in situ oxidation of H2S in environmental water at a construction site. This study reports the practical application of this advanced technology and the system performance.

"The authors have packaged the information with a very wide range of tables, figures, key equations and source references. Many readers will find all they ever wanted to know about tunnel construction without leaving its pages; while those for whom it whets the appetite to dig deeper (pun intended!) will find comprehensive pointers to up-to-date sources of literature elsewhere."

High tunnel hoop houses are a type of greenhouse structure. They are built on the ground and are large enough to walk into. For heat, they rely on passive solar heating. They are practical and economical to build.

Hoop houses, cold frames, and high tunnels are all types of greenhouses with similar designs. The hoop house gets its name from its shape, although houses can be constructed with straight lines using elbows to get the desired shape for a building. The shape of a hoop house sheds water and snow from its exterior while allowing sunlight in to provide heat.

High tunnel hoop houses are relatively inexpensive to construct, costing around $2.50 per square foot, with low maintenance once constructed. They are easy to build and adapt to small or large land units to meet the needs of gardeners and farmers alike.

Since plants need sunlight to grow, light penetration should be a concern in structure design. Grow lights can be used, but these require an electrical source. In areas where wind and snow are common, consider the load limitations the structure must have to endure stress. The height of the hoop house can be adjusted by lengthening the rib pipes so that you can walk and work inside comfortably; therefore, you should think about height before construction starts.

Select a site that is moderately level with good drainage and good soil if you plan to plant directly into the soil. A site can be modified by soil fill so that construction is on a pad. Select a site in an open area where trees and other obstacles will not affect sun penetration or create shadows (Figure 1).

Consider the surrounding area so the structure will be protected against high winds and heavy snows to help extend its life. Water will be needed in the high tunnel, and electricity may be an option you may want to consider. Security and protection against vandalism of the high tunnel hoop house and crop may also be a factor to consider when selecting a site.

Along both lengths of the high tunnel hoop house and inside the string, drive 24-in. rebar stakes every 4 ft apart, 12 in. deep, at a 30-degree angle, until you reach the desired length of building (Figure 3).

We recommend using 2-in. PVC because it holds up well to winds blowing 50 mph and the occasional snow 10 in. thick on the plastic. Use new plastic pipe for construction because weathered pipe will be brittle and break when bending. Once the pipes for the hoops have been bent and weathered, the pipe will retain its bent shape and can be reused for another hoop house project.

There are three 3/4-in. PVC pipes running the length of the inside of the high tunnel hoop house that will be used for stability, and can be used to install sprinklers or drip irrigation once your house is completed. These PVC pipes will be placed on the 1 in. 4 in. 32 ft side batten boards that were installed in the previous step. Use 3/4-in. conduit saddles to hold the pipes to the wood. Use 2-in. screws to attach the wood to the 2-in. PVC rib pipe. The third 3/4-in. pipe and batten board will be put in the center inside of the high tunnel (Figure 8).

When the uprights are set, frame the bottom and the middle from the door frame to the 2-in. plastic rib pipe using 24s cut to size; refer to Figures 10 and 11 for examples. Then construct a door using 24s to fit into the door frame and attach with door hinges. This is done at both ends of the high tunnel hoop house frame (Figures 12 and 13).

Cut a piece of plastic that is around two feet longer than the total length of the hoop house; this will give you extra plastic to pull on while stretching the plastic over the frame. Pull your greenhouse plastic over your high tunnel hoop house frame. Be very careful that the plastic does not hook onto anything when pulling it over.

SuperMap and partner company has established standard models, shield groups, and BIM management platforms for tunnel construction, which has realized the visualization expression of tunnel shield environment with the goal of dynamic shield safety risk management based on BIM informationization and the safety risk management of the construction site, and provided applications of multi-source geological modeling, geological prediction, shield safety risk management, and guidance for construction and others.

The environmental modeling includes establishing models of risk sources and buildings on the ground, importing BIM platforms, and displaying projects in virtual reality; geological model includes making 3D geological models based on drilling and CT related geophysical data; the shield tunnels modeling includes the modeling of shield machine, tunnel segment, track, pipeline, lining, etc., the model can be imported into the BIM platform after light-weighting.

The BIM platform integrates real-time shield machine data, camera monitoring data, intelligent monitoring data (settling, deformation, displacement, stress, pressure, groundwater level, etc.), provides manual monitoring report data importing and mobile inspection reporting, and integrates third-party security hidden danger system data, etc. By integrating multi-party data and comprehensive visual analysis, the islands of information can be avoided and construction safety can be ensured. 041b061a72


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