Slurry Shield Research Articles

Construction of slurry shield tunnel under Huangpu River in Shanghai

This paper presents a case history of slurry shield tunnel constructed under Huangpu River in the urban area of Shanghai. The tunnel was the second Yan'an Road tunnel used to connect the western part and the eastern part (the New Development Area) of Shanghai, as shown in Fig. 1. The length of the tunnel was 2270.5 m, in which 1310.5 m was constructed by using slurry shield machine (SSM). The inner and outer diameters of the tunnel were 9.9 and 11m, respectively. The outer diameter of the shield was 11.22 m. Tunnel was constructed under very difficult geotechnical and environmental conditions. The soil type of the tunnel passing through was very soft mucky clay. This was a deltaic deposit of Yangtze River. The soft mucky clay had the water content greater than its liquid limit, low hydraulic conductivity, low shear strength, and high sensitivity. The sensitivity ratio of soft mucky clay at the construction site was around 5. Under Huangpu River, the overburden earth was 6.59 m and was only 0.6 times the tunnel diameter. The tunnel also passed under 25 buildings in the west side and 15 buildings in the east side. One building's bottom slab was only 0.68 m above tunnel crest. Shield passed among the pile foundations of this building. There were also many pipelines such as gas pipe, water supply and sewerage pipes, and telephone and CATV cables under the road. In order to reduce the disturbance to the surrounding ground, careful operation was adopted and movement of surrounding ground was monitored. Countermeasures such as controlling of slurry pressure of chamber, excavation speed, washing pressure, slurry treatment, and real time grouting, etc. were carefully regulated to the geotechnical and environment conditions during construction. Some controlling technique was proposed based on the monitoring results during construction. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Twenty years of micro-tunnelling in Singapore

Singapore enjoys a clean and healthy environment today. It is largely because of the comprehensive sewerage infrastructure construction programs implemented throughout the nineteen seventies and eighties during the very early stages of Singapore's development. During the past three decades alone the sewer network expanded more than threefold to the extent that there are about 2900 km of sewers of diameters ranging from 150 to 3000 mm in the island. In the past decade alone, more than 500 km of sewers were added, most of them constructed by trenchless methods. In addition, Singapore will soon add 48 km of very deep sewers of diameters ranging from 3.3 to 6 m and another 70 km of link sewers of diameters ranging from 0.75 to 3 m to the sewer network. Singapore is the first country outside of Japan to use micro-tunnelling technology in 1983 for trenchless sewer construction. Since then many countries have also adopted and used the technology successfully, notably the United States in 1984, Germany in 1984, United Kingdom in 1985, Middle East Countries in 1987 and Australia in 1989. Today, most countries use trenchless technology in one form or another. Several types of macro and micro shields for trenchless sewer construction have been used in Singapore over the past two decades. Macro shields such as slurry shield and earth pressure balance shield have been used for installing sewers of larger diameters ranging from 900 to 6000 mm. Micro shield systems such as earth arrow, iron mole, horizonger and mini slurry shield have been used for installing hundreds of kilometres of sewers of diameters ranging from 225 to 900 mm. The micro-tunnelling works in Singapore has undergone a tough test as often micro shields had to go through varied soil geology commonly encountered in Singapore. Despite the problems caused by the difficult soils, the contractors have successfully installed trenchless sewers to high degree of accuracy. Singapore's experience has demonstrated that the trenchless method is efficient, fast and cost effective for installing sewers in builtup urban areas. Singaporean sewerage system designers took advantage of the trenchless method and designed deep trunk sewers to reduce the need to construct more pumping stations in public housing estates. This is a very interesting spin off from trenchless sewer construction methods as the deep sewers are no longer expensive and difficult to construct. The extensive use of micro-tunnelling and other modern tunnelling technologies for trenchless sewer construction have given extra confidence to Singapore to implement a mammoth Deep Tunnel Sewerage System (DTSS), involving construction of about 48 km of deep sewers of diameters ranging from 3.3 to 6 m in tunnel and another 70 km of link sewers of diameters ranging from 0.75 to 3 m by trenchless methods. Singaporean engineers have provided engineering consultancy in micro-tunnelling technology to countries in the region. Such works include micro-tunnelling projects executed in Sydney and Melbourne in 1995/96 in which not only engineering consultancy was provided by Singaporean engineers but also micro-tunnelling technicians from Singapore undertook micro-tunnelling operations for a contractor in Melbourne. Also, in 1998 Singapore's expertise in micro-tunnelling enabled a consulting firm to pioneer micro-tunnelling work in India by providing engineering consultancy to the Municipal Corporation of Greater Mumbai for a World Bank financed micro-tunnelling project to install 4.7 km of missing sewer links across railways and narrow streets. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Construction of shaft tunnel by slurry pipe jacking through sedimentary ground under high water pressure

Pipe jacking technology has been developed rapidly in recent years to satisfy demand for distances of more than 1 km or curves of less than 10 m radius. A shaft tunnel driven by pipe jacking, another type of development, was adopted in order to provide ventilation to the Imaigawa underground reservoir tunnel under the national highway in Yokohama, Japan, which has been temporarily in service since 2001. Downward excavation of the 2000 mm ID ventilation tunnel starts from ground surface and reaches to the crown of the existing 10,800 mm ID reservoir tunnel, which is located 87.8 m deep, through the stiff clay layer. Depression angle of the tunnel is set as 75.6 degrees since the ventilation building is constructed in the existing park along the highway. Pore water pressure at the arrival is 0.66 MPa. This project is one of the largest in this type of tunnels in Japan. This paper focuses on equipment and facilities adopted on the project and construction methodology of the inclined pipe jacking. Specially-designed equipment and facilities were planned and employed to overcome anticipated difficulties; namely shield machine, jacks and reaction frame, lift-preventer, inclined elevator, and survey system. Slurry shield machine was specially designed considering the high water pressure, stiff clay excavation, accurate directional control, connection work to the existing reservoir, and simple dismantling. It shall be noted that the machine can not access the existing reservoir tunnel and the dismantled motors of the machine had to be removed through the tunnel driven. The thrust jacks and reaction frame were designed to facilitate easier setting of pipes and ground anchors were used against the reaction force of up to 8000 kN. To prevent the lift due to buoyancy to the shield machine and pipes during excavation, which was significant when the thrust jacks are released, the lift-preventer with power casing jack and ground anchors were developed. Inclined elevator, which is used for pipe connection and maintenance, was designed in such a way that it moves to give space to the pipe setting. Since accuracy was vital for the tunnel drive, survey system with laser theodolite and non-prism laser distancemeter (with automatic target recognition), which enables constant monitoring, was adopted. Relatively complicated construction sequence was developed bearing smooth operation and safety in mind. It was however completed successfully due to the well-prepared sequence. This method is considered effective for inclined shaft construction, such as ventilation shafts or access tunnels. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Observational control of slurry shield tunnels with super close spacing under the nearby bridge abutments loads

The Rinkai Line is a new railway line of around 12.3 km in length, connecting Shin-Kiba Station with Osaki Station through the new Tokyo subcentre on the waterfront in Tokyo. On March 1996, a section of about 4.9 km between Shin-Kiba Station and Tokyo Teleport Station was put into service as a first phase. As part of a second-phase construction, the Rinkai Line Higashi-Shinagawa Tunnels have been constructed by slurry shield tunnelling method. This tunnel project stretches about 983 m from Tennozu Isle Station to Shinagawa Seaside Station. This project required that the parallel twin tunnels had very close clearance (the minimum clearance 1/4 0.6 m). Furthermore, tunnel excavation was located very close to some important existing sensitive structures, such as abutments of bridge and an oil tank. At the Higashi-Shinagawa bridge section, the shield drove through just underneath the piled foundations with the minimum clearance of around 3.0 m. Mair and Taylor (1997) reported some case histories related to the response of buildings on piled foundations to ground movements induced by tunnel process. However, very limited published case histories related to the evaluation on the effect of tunnelling on piled foundations exist so far because of including the complex interaction mechanisms. Therefore, careful management of the tunnelling works was required. In order to prevent excessive settlements and to ensure the safety of the adjacent existing structures, detailed in situ monitoring of the nearby structures, surface and subsurface ground movements was planned and implemented. An automatic measuring system was adopted as a measure of controlling ground movements, and the optimum control value was established for soil pressure inside the shield chamber for stabilizing tunnel face. Furthermore, the monitoring of segmental lining was also carried out to confirm the safety of the segmental lining design at very closely excavated sections. At the Higashi-Shinagawa bridge section, grout injection from the preceding shield was planned and carried out to stabilizing the surrounding ground as an auxiliary measure. It worked quite well to suppress the loosening of the surrounding grounds and the movement of the piled foundations. This paper describes the in situ monitoring results of the existing bridge pier movement during the shield construction. Main conclusions are as follows: (1) By careful and well-controlled tunnel excavation, detailed monitoring of the ground movements and rapid data processing, it has achieved well-controlled volume losses to values less than 0.5% in spite of the tough tunnel construction with super close spacing and the existing nearby structures. (2) Bridge pier's settlements were well controlled, being less than 4.0 mm, and the shield construction has successfully completed without any problems. (3) The grout injection from the inside of the preceding tunnel could effectively control the loosening of the surrounding grounds and the pile settlements. (A) Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Excavation of Japan’s largest shield tunnels in the heart of Tokyo Metropolitan area - the Nishi-Shinjuku Tunnel

The Metropolitan Expressway is the main transportation route in the Tokyo Metropolitan area in Japan, with an average 1.15 million vehicles and an estimated two million users per day. In order to further improve the expressway network, an additional 46 km Central Ring was planned and constructed. Part of the Central Ring is the Shinjuku Line, which is approximately 11 km long and almost entire length was constructed below ground in bored tunnel. The Nishi Shinjuku Tunnel, forming a section of the Shinjuku Line, comprises of identical twin tunnels with outside diameter of the tunnel segment is 13.0 m. Each of the tunnels was designed to cater for traffic in one direction; each with two traffic lanes and about 600 m in length. Excavation of the tunnels was carried out by a pressurised slurry shield machine with an outside diameter of 13.23 m. The excavation operation commenced from a common launching cum receiving shaft, proceeded under an existing road for about 600 m until it reached an intermediate vertical shaft. The shield machine turned 180 degrees within the vertical shaft and headed back to the common launching cum receiving shaft, completed the twin tunnels with a total length of about 1200 m. Due to the location of construction site in the middle of the city, there was limited working space on the ground level. As such most of the temporary facilities including slurry treatment plant, slurry conveying equipment, sand screening device, back grouting equipment, etc. were installed inside the common launching/receiving shaft. The intermediate vertical shaft for rotation of the shield machine is located in gravel and sand formations with high water permeability and high pore water pressure. In order to protect the wall of vertical shaft from collapsing during arrival and re-launching of the shield machine, as well as to prevent water seepage, ground treatment work was conducted by the Freezing Method. The freezing Method was selected because of its outstanding performance in sealing off underground water and ability to create a high strength ground protection. In addition, swelling effect resulting from freezing process was relatively small in gravel and sandy soil layers and therefore impact on the surrounding ground formation was limited and/or negligible. Although there were quite a number of projects involving turning of shield machines with outer diameters of less than 7 m (weight below 350 ton) previously, there was no precedence for turning of large shield machine of this scale with a weight of 3000 ton. Therefore, various type of turning methods were thoroughly reviewed and a turning method using ball-bearings (each of the steel balls was /90 mm in size) with the assistance of two numbers of 400 ton · 2100 mm hydraulic jack, which is low cost and safe to execute, was selected. The whole turning operation took four days to complete, two days for the 180 degrees turn and another two days for lateral movements before and after the rotation. Excavation of the tunnels started in September 2000 and was successfully completed as scheduled in February 2002. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

Ground movements due to the construction of cut-and-cover structures and slurry shield tunnel of the Cairo Metro

This paper presents an evaluation of the settlement prediction techniques used to estimate the surface settlements associated with the construction of the Greater Cairo Metro Line 2. The construction of the Cairo Metro involved the construction of cut-and-cover underground stations and bored tunneling. A typical underground station was executed using top-down construction technique. The twenty two meters excavation was carried inside a watertight ☐ with 50-m-deep diaphragm walls to form the sides and a 7-m thick grouted plug at the bottom. Tunneling was performed using a slurry shield tunnel boring machine, TBM, having an internal diameter of 9.48 m. This analysis is the first step in view of enhancing the procedures of settlement prediction and appraising potential damages to overlying structures and utilities for the future construction of the twin road tunnels in the historical urban environment of Al Azhar area and Khan El Khalily market in Cairo.

Observations of Ground Movements during Tunnel Construction by Slurry Shield Method at the Docklands Light Railway Lewisham Extension—East London

This paper describes monitoring results of ground movements due to slurry shield tunnelling on the Docklands Light Railway Lewisham Extension (hereinafter referred to as DLR). The DLR tunnels (twin bored tunnels) run from Island Gardens Station to Greenwich Station in East London, passing under the River Thames, a distance of around 4.2 km. The construction of the tunnels, which were at shallow depth, needed an extensive appraisal of the potential damage induced by ground movements to the overlying and underground structures. Therefore, in order to effectively minimize the ground movements, a slurry shield machine with a diameter of 5.85 m was employed. Careful control of excavation was carried out during shield tunnel construction. As a result, the slurry shield tunnelling method in Woolwich and Reading Beds by well controlled monitoring was successfully conducted, leading to volume losses less than 1.0%. This paper focuses on the ground surface movements, particularly the transverse and longitudinal settlement profiles, and volume losses during shield tunnel construction, in relation to the ground conditions. Based on the monitoring results, combined with previous centrifuge model test results and other field monitoring data, practical methods to appropriately predict ground movements due to shield tunnelling are proposed.

DEVELOPMENT OF THE REMOVABLE THREE-CENTERED SLURRY SHIELD METHOD FOR STATION USING RUNNING SHIELD MACHINE

DEVELOPMENT OF THE REMOVABLE THREE-CENTERED SLURRY SHIELD METHOD FOR STATION USING RUNNING SHIELD MACHINE

The face stability of slurry-shield-driven tunnels

During the excavation of a tunnel through soft water-bearing ground, a temporary support is often required to maintain the stability of the working face. In a slurry shield, this support is provided by a pressurized mixture of bentonite and water. Slurry-shield tunnelling has been applied successfully worldwide in recent years. Under extremely unfavorable geological conditions, however, face instabilities may occur. This paper aims at a better understanding of the mechanics of face failure when using a bentonite slurry support. The complex interrelations between the various parameters (shear strength and ground permeability, suspension parameters, slurry pressure, geometric data of the tunnel, safety factor) are studied. Attention is paid to the time-dependent effects associated with the gradual infiltration of slurry into the ground ahead of the tunnel. Related topics, such as the stand-up time, soil properties and the effect of advance rate, are discussed quantitatively. Le creusement d'un tunnel dans un terrain meuble nécessite souvent un soutènement temporaire afin de stabiliser le front de taille. Dans le cas d'un bouclier à boue, cette pression de stabilisation est réalisée par un mélange de bentonite et d'eau sous pression. Durant ces dernières années, grâce à une évolution technologique importante, l'utilisation de boucliers à boue pour la réalisation d'ouvrages souterrains a convu un succés mondial. Pourtant, face à des conditions géologiques extrêmement défavorables, des problèmes majeurs de stabilité du front de taille peuvent se présenter. L'article présent a pour objectif d'améliorer la compréhension de la mécanique de la rupture du front de taille pour le cas d'un front stabilisé par de la boue à base de bentonite. On étudie les relations complexes entre les différents paramètres (résistance au cisaillemment et perméabilité du sol, pression de boue, données géométriques du tunnel, coefficient de sécurité) en tenant compte des effets transitoires dûs à l'infiltration progressive de la boue dans le sol en avant de l'avancement. En outre, d'autres sujets comme le temps pendant lequel le front de taille reste stable ou l'influence de la vitesse d'avancement sont discutés quantitativement.

AN EXPERIMENTAL STUDY ON THE OPTIMUM PROPERTIES OF SUSPENSION FOR SLURRY SHIELD TUNNELING IN GRAVEL GROUND

AN EXPERIMENTAL STUDY ON THE OPTIMUM PROPERTIES OF SUSPENSION FOR SLURRY SHIELD TUNNELING IN GRAVEL GROUND

泥水シールド工法における固化材凝集泥水の再生方法

It has been known that cement stabilizers cause the cohesive deterioration of slurry for slurry shield in the excavation of cement stabilized ground. So the research on the efficient regeneration method of deteriorated slurry has been longed from a viewpoint of discharged sludge reduction.The basic experiments have been carried out regarding the deterioration and regenerarion of seawater slurry in which cement stabilizers and dispersants are added.As a result, the following points have been clarified.1. Seawater slurry can be used for slurry shield within a certain extent of clay concentration in the slurry.2. The slurry deterioration occurs depending on the cement quantity that is mixed in the slurry in excavation of ordinary stabilized ground.3. Lignosulfonate dispersant is the most effective and economical to regenerate the deteriorated slurry.

Drive by world's largest slurry shield is launched in Tokyo; Japan's largest EPB shield completes a 54-m drive

Drive by world's largest slurry shield is launched in Tokyo; Japan's largest EPB shield completes a 54-m drive

The effect of tunnelling technology on ground control

The effects of tunnelling technology on ground control are studied for the Hydroshield Boring Machine. The studies are based on field measurements obtained at a tunnel in sand constructed for the Light Rail Transit system in Edmonton, Canada. Particular attention is given to the relationships between the slurry pressure and face displacements, between the grout pressure and the tail displacements, and between the liner convergence and the final displacements. The results are generalized using the concept of a Ground Reaction Curve. Different curves are obtained for different stratigraphic conditions and for different grout pressures. The results are fundamental for understanding the relative importance of various sources of ground displacements (face, tail, liner), as well as for a quantitative insight into the mechanics of ground-support interaction for a slurry shield. The results also have direct practical significance for design decisions (slurry pressure, grout pressure, stiffness of liner) associated with this tunnelling technique. Les effets de la technologie de creusement de tunnel sur le contrôle desmouvements de sous-sol sont étudiés dans le cadre de la machine à forer type ‘Hydroshield’. Les études sont basées sur des mesures faites lors de la construction d'un tunnel dans du sable pour le Light Rail Transit System à Edmonton au Canada. Une attention particuliére est prêtée aux relations qui existent entre la pression de la bentonite et les déplacements à l'avant du tunnel, entre la pression du béton et les déplacements à l'arrière du tunnel, entre la convergence du revêtement et les déplacements finaux. Les résultats sont généralisés à l'aide d'une courbe de réaction du sous-sol. Différentes courbes sont obtenues pour différentes conditions stratigraphiques et différentes pressions du béton. Les résultats sont d'une nature fondamentale d'une part pour la compréhension de l'importance relative des différentes sources de déplacement (avant, arrière et revêtement), et d'autre part pour obtenir une idée quantitative de l'interaction entre le support et le sous-sol. Les résultatsont une signification pratique directe pour le choixdes paramètres de construction (pression de la bentonite, pression du béton, rigidité du revêtement) associées avec la technique de creusement du tunnel.

Design of the shield tunnel for the trans-Tokyo bay highway

The Trans-Tokyo Bay Highway project is the first phase of an ambitious plan to connect Kawasaki and Chiba by a 15-km crossing of Tokyo Bay. The crossing involves a 5-km bridge, a 10-km undersea tunnel, and a manmade island in the middle of the bay. The construction method for the undersea tunnel must take into account the large external diameter of the primary lining (approx. 14 m); the extremely soft ground under the sea; the extremely high water pressure to which the tunnel will be subjected; and active seismic conditions in the Tokyo Bay area. This paper discusses the slurry shield tunnelling method adopted for the undersea tunnel portion of the project. L'autoroute Trans-Tokio-Bay est la première étape d'un plan ambitieux qui a pour but de connecter Kawasaki à Chiba, en traversant la baie de Tokyo. Le projet inclut un pont de 5 km, un tunnel sous-marin de 10 km et une île artificielle au milieu de la baie. La méthode de construction utilisée pour le tunnel doit tenir compte du diamètre intérieur important du revêtement primaire (à peu près 14 m); du terrain extrêment peu consolidé; de la pression d'eau considérable à laquelle le tunnel sera soumis; et des conditions sismiques actives dans la baie de Tokyo. Le présent article discute la méthode de creusement utilisée pour la partie sous-marine du projet, à savoir un bouclier à la bentonite.

Villejust Tunnel: slurry shield effects on soil and lining behaviour and comments on monitoring requirement : Leblais, Y; Bochon, A Proc Tunnelling '91, London, 14–18 April 1991P65–77. Publ London: Elsevier, 1991

Villejust Tunnel: slurry shield effects on soil and lining behaviour and comments on monitoring requirement : Leblais, Y; Bochon, A Proc Tunnelling '91, London, 14–18 April 1991P65–77. Publ London: Elsevier, 1991

Tunnel face stability in slurry shield tunnelling : Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13–18 August 1989 V2, P775–778. Publ Rotterdam: A A Balkema, 1989

Tunnel face stability in slurry shield tunnelling : Proc 12th International Conference on Soil Mechanics and Foundation Engineering, Rio de Janeiro, 13–18 August 1989 V2, P775–778. Publ Rotterdam: A A Balkema, 1989

Massive mixshield changes mode at Grauholz : Wallis, S Tunn TunnlgV22, N9, Sept 1990, P25–28

The article discusses the rail tunnel project at Grauholz near Bern where construction methods are challenging tunnelling conventions. In this construction project use is being made of the largest Mixshield yet made, at 11.6m O/D, which is to be converted from a bentonite slurry shield to a non-pressurised disc cutting machine and back again during the course of its 5.5km long drive, to avoid dewatering operations in an environmentally sensitive area. As the TBM advances the tunnel surface is lined with precast concrete segments and the invert is backspilled to provide the permanent foundation for the railway track. (Author/TRRL)

Tunnelling machines in soft ground: a comparison of slurry and EPB shield systems

Thanks to advances in tunnelling machine technology, tunnels can be driven by machines even in very difficult ground conditions. The two most important objectives in machine tunnelling are: (1) to support the ground reliably during excavation; and (2) to hold the surrounding ground behind the shield tail in balance by grouting while the lining is being erected. The author compares two established machine tunnelling methods—the slurry shield and the earth-pressure balanced shield tunnelling system—with regard to how they achieve these two objectives.

CONSTRUCTION OF A DEEP SHAFT AND A SHIELD TUNNEL UNDER A HIGH WATER PRESSURE AT OSAKA BAY

Sakai Koro Tunnel is a shield tunnel constructed under Osaka bay. This tunnel is used for transportation of natural gas. The length of the tunnel is 2130m and the deepest level of the tunnel is 45m below the ground level. The two driving shafts were constructed by the method of pneumatic caisson employing ground freezing. One of the shafts is 52m in depth and one of the deepest shafts in Japan. Sandy layer with gravel under high water pressure of 4.5kgf/cm2 was excavated from the both shafts by slurry shield method. These tunnels were connected under the sea by employing ground freezing method. Since a part of the tunnel is subjected to consolidation settlement of the ground in future, elastic washers and flexible segments were installed into the tunnel at the appropriate places to release the influence.

EXPERIMENTAL STUDY ON THE SUITABLE SLURRY PRESSURE IN A SLURRY TYPE SHIELD

EXPERIMENTAL STUDY ON THE SUITABLE SLURRY PRESSURE IN A SLURRY TYPE SHIELD