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6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
6. cellar constructions
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6. cellar constructions

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  • 1. CT3300 Use of Underground Space6. Cellar constructions6.1 IntroductionA cellar construction is a structure with a limited physical range. Methods that can be used to create a(deep) cellar construction are discussed in the following sections. Some techniques used to create acellar construction were already discussed in chapter 5 “General construction methods”.6.2 Open building pitThe cellar construction is usually built separate from the pit wall. In some cases, such as undergroundparking garages, the earth-retaining structure (steel sheet pile wall or concrete diaphragm wall) is alsothe permanent wall of the cellar construction.A solid wall made with chemical injections or jet grouting is used only in special cases. Usually itconcerns a structure where a cellar or tunnel is situated adjacent to an existing building or situated at acritical depth in relation to the building. This is shown in figure 6.1. Under this building a solid wall isput in, which prevents inflow of groundwater. When the building is made on a raft foundation, the solidwall also has a supporting function.Figure 6.1: Injection against / under an existing building6 Cellar constructions 72
  • 2. CT3300 Use of Underground Space6.3 Polder principleIn a cellar construction, built according to the polder principle, the bottom seal consists of a naturallow-permeable layer. The vertical boundary is formed with a sheet pile wall.The seepage water has to be pumped out permanently. Due to the direct contact with thegroundwater, the air humidity level in the cellar will be very high. That is why the polder principle isoften applied to underground parking garages, because for these there is no regulation regarding airhumidity. The floor of the parking garages usually consists of clinker paving.Figure 6.2: Parking garage, built according the polder principle6.4 Cut-and-cover methodIn cases where the above ground infrastructure has to be restored as soon as possible, the cut-and-cover method is a good option for cellar construction. After the required depth is reached, the cellarroof is constructed. Figure 6.3 shows a cut-and-cover method application located in a park.A variant of the cut-and-cover method is the simultaneous construction of the super and sub structure.This variation starts with the construction of foundation piles and cellar walls. Subsequently the superstructure is built on top, while the cellar is simultaneously constructed. This means the construction isgoing both upwards and downwards from the surface level. On one hand, the time necessary toconstruct the entire building is reduced; on the other hand, the disadvantage of this variation is a morecomplicated execution process.6 Cellar constructions 73
  • 3. CT3300 Use of Underground SpaceFigure 6.3: Kiba park site, cut-and-cover method6 Cellar constructions 74
  • 4. CT3300 Use of Underground Space6.5 Pneumatic caissonA cellar construction built using the pneumatic caisson method can be considered for situations whenthere is not much space and / or when it is not permitted to extract groundwater.Figure 6.4 shows the execution phases for the construction of a tunnel beneath a river (the SendaiboriRiver Crossing Project). Pneumatic caissons were used as foundation for the tunnel. Furthermore thesoil was frozen as a temporary measure during the construction of the tunnel.Figure 6.4: Tunnel crossing the Sendaibori River, pneumatic caisson6 Cellar constructions 75
  • 5. CT3300 Use of Underground Space6.6 Special examplesFigure 6.5a shows the combination of a cellar construction and a bored tunnel that is situated at greatdepth. The phases of execution are shown in figure 6.5b and the longitudinal section is shown in figure6.5c.Figure 6.5a: Shinjuku station, connection of a cellar construction within a bored tunnel at great depth6 Cellar constructions 76
  • 6. CT3300 Use of Underground SpaceFigure 6.5b: Phases of execution.6 Cellar constructions 77
  • 7. CT3300 Use of Underground SpaceFigure 6.5c Longitudinal section6 Cellar constructions 81
  • 8. CT3300 Use of Underground Space6.7 Execution problemsThe main execution problems of cellar construction appear in the urban environment. The lack ofavailable space and level of acceptance for hindrance during the building process mean that theexecution is restricted by many requirements, especially requirements regarding the groundwaterlevel. In the urban environment de-watering on a great scale is often not permitted, because it cancauses settlement. To prevent this, a good design for the execution of the cellar construction isrequired, which usually implies a design that avoids de-watering.When de-watering is not allowed and a natural impermeable layer is not present, one of the problemsof the cut-and-cover method is the building of an underwater concrete floor, which is anchored bytension piles. The piles can be rammed from street level. A problem with this method is that they thenmight form an obstacle during excavation. To implement piles or anchors under an already built roof isalso very difficult. A grout-bow as described in section 6.10 could be a solution to this problem.Working under increased air pressure is also a solution to the above-described problem.Decompression times have to be taken seriously (see also chapter 5), which decreases the effectiveworking time and thereby increases the building costs.In certain circumstances the required execution time can be a very important criterion in the choice ofa building method.6.8 Building costsThe building costs and execution times for cellar construction are strongly determined by the chosentechnique.The building costs roughly consist of the following costs:• Planning / engineering• Foundation• Building pit• Groundwork• Concrete work• Installations• Construction site costs• General costs, profits and risks.In the KIVI-report for cellar constructions [KIVI, 1994, Kelderconstructies; Op naar de diepte!] a costcomparison was made for a cellar construction under various geological circumstances and withvarious building methods.6.9 Dutch situationThe presence of a high groundwater table has a large influence on the execution of cellarconstructions in The Netherlands (especially in the western part of the country). Besides thesegeotechnical and geohydrological circumstances there are additional challenges to be found withregards to existing constructions and the urban environment. The building methods that are applicableare restricted to open building pit, polder principle, caisson method and the cut-and-cover method.6 Cellar constructions 82
  • 9. CT3300 Use of Underground Space The cut-and-cover method was hardly used in The Netherlands, but during the last years there have been a number of projects where this method was applied. The subway station Wilhelminaplein in Rotterdam and the tramtunnel Grote Markstraat/Kalvermarkt in The Hague are examples of this. The subway station Wilhelminaplein is unique since it was built around the existing subway tunnel. The execution phases are shown in figure 6.6. The roof (thickness: 2,5 m) was poured over the steel combination wall at ground level (fig. 6.6a). Beneath the roof excavation took place until the top of the tunnel was reached. Then the roof of the tunnel was strutted against the roof to prevent floating of the tunnel in case of de-watering disturbances. The combination wall was also strutted with a horizontal strut, which guaranteed the horizontal stability of the tunnel during excavation (fig. 6.6b). Tension piles were put in place, after which the floor of the new station could be poured. Furthermore concrete walls were constructed against the inside of the combination walls (fig. 6.6c). Once the temporary strutting was replaced by the permanent V-shaped strutting, the side walls of the original tunnel were removed, after which the completion of the station could take place (fig. 6.6d).Figure 6.6: Cross section station Wilhelminaplein during various execution phases 6 Cellar constructions 83
  • 10. CT3300 Use of Underground Space The tramtunnel Grote Markstraat in The Hague used a grout layer as bottom sealing. This is shown in figure 6.7. The bow that can be seen at the bottom of the tunnel was made by jetgrouting from street level. The upward groundwater pressure is transferred to the diaphragm walls by the bow-shape. This project has become notorious for water leakages that occurred. Horizontal grout layers should have been implemented to a greater depth; the diaphragm walls should have been constructed to a greater depth. This would have been a more expensive solution, but it could have prevented the problems that occurred. In the end the project was delayed for a number of years. When the project was finished, the concrete floor shown in figure 6.7- 6 took over the water retaining function. Figure 6.7: Basement Grote Markstraat, cut-and-cover method with grout-bow6 Cellar constructions 84

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