Ground Stability Analysis in Non-Open-Cut Tunneling Method Using Small-Diameter Steel Pipe Piles

Jonguk Kim,Hafeezur Rehman,Hankyu Yoo,Jung-Joo Kim

doi:10.3390/app10196906

Jonguk Kim, Hafeezur Rehman + Show 2 more

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https://doi.org/10.3390/app10196906

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Abstract

The non-open-cut method is used for constructing tunnels under existing roads without blocking traffic. Various non-open-cut methods use pipe roofs made of medium- and large-diameter steel pipe piles. However, the risk of ground settlement or heave is involved during the application of such piles. Therefore, research is conducted through model tests and numerical analysis on the non-open-cut method to investigate these problems using small-diameter piles. The progress of tunnel construction is divided into two repetitive steps. The first step (Stage 1) involves pulling back the pressure panel, and the second step involves propelling the precast structure (Stage 2). The behaviors of the pipe piles and ground displacement are analyzed according to the cover depth, tunnel size, existence and nonexistence of the shoe structure, and progress of tunnel construction. Small-diameter piles reduce the displacement during both stages. With a decrease in cover depth, the stress acting on the pile decreases during Stage 1 and increases during Stage 2. The presence of the shoe structure reduces the stress on the pile during both stages. The ground behavior based on the construction progress indicates that the ground settlement increases during Stage 1; however, no correlation is observed during Stage 2 at low depth.

Highlights

Owing to an increase in the urban population, traffic has become a major issue in the megacities of the world
In the pipe roof structure (PRS), tubular roof construction method (TRcM), new tubular roof (NTR), and roof panel shield (RPS) methods, the tunnel is constructed by placing concrete under the roof that is formed by each method of arranging the steel pipes
In the presence as well as absence of piles, with a decrease in cover depth, the heave of the ground surface increased owing to the small overburden load, because the load counters the force of heave (Figure 22)

Summary

Introduction

Owing to an increase in the urban population, traffic has become a major issue in the megacities of the world. To overcome this issue, road networks in large cities are becoming increasingly complex. The more complex a road network becomes, the more often a new road is constructed under the existing road When such a construction has to be undertaken without interrupting the traffic, the non-open-cut method of tunneling is used. Several non-open-cut methods, such as the pipe roof structure (PRS), tubular roof construction method (TRcM), new tubular roof (NTR), roof panel shield (RPS), and front jacking methods, are used for constructing tunnels under existing roads. During tunnel construction using medium- and large-sized (800–2800 mm) steel pipes, ground settlement or heave may occur during

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