Tunnel-boring in soft soil: A study on the driving forces applied to a slurry-shield TBM

Tunnel-boring in soft soil: A study on the driving forces applied to a slurry-shield TBM

Report on Underground Solutions for Urban Problems

World wide, we see developing nations building new infrastructure as well as developed cities rehabilitating and expanding their infrastructure to meet the demands of increased population, energy efficiency, and environmental awareness of the public. Ten years ago ITA issued its special edition of the Tribune entitled “Why Go Underground,...

Geo-engineering: A co-production of applied earth sciences and civil engineering - 2nd phase

Detecting defects in diaphragm walls prior to excavation

Recent incidents with leaking diaphragm walls during construction of subway lines in Amsterdam and Rotterdam (Netherlands) have led to reconsideration of the diaphragm wall as a retaining wall construction for deep excavations. In our opinion the joints between the panels are the weak spot. During concrete pouring the concrete should replace the...

The use of 3D depth cycloramas in municipal processes

The use of digital panoramic imagery in processes at municipal and cadastral authorities has become common over the last decade. Applications are found among situational awareness, inventory of public areas, real estate valuation, assessment of permits and inspecting security risks. More and more the imagery is being used for measuring and map...

Combined full field stress and strain measurement methods for granular materials

The current paper re-introduces the photoelastic measurement method in experimental geomechanics. A full-field phase stepping polariscope suitable for geomechanical model tests has been developed. Additional constraints on the measurement and mechanical setup arising from geomechanical test conditions are outlined as well as the opportunity to...

Small incidents, big consequences. Leakage of a building pit causes major settlement of adjacent historical houses. Amsterdam North-South metro line project

The construction of the North-South metro line project in Amsterdam (the Netherlands) is ongoing for the last five years and until recently suffered no major construction incidents. In the summer of 2008 two leakages occurred in one of the building pits of the deep stations. These leakages caused major settlement of a number of historical houses...

Measurement of stress and strain development around a pile in a photoelastic granular material

This paper presents the results of model pile penetration in a photoelastic material. The soil in this test is represented by an assembly of photoelastically sensitive glass particles. This allows for the determination of stresses in the assembly by the photoelastic method. Displacements around the pile are measured using digital image...

Horizontal Cone Penetration Testing

It has been proposed to use horizontal cone penetration tests froma tunnel boringmachine to obtain additional information on the soil in front of the TBM. This article gives an overviewof various investigations into the feasibility of such a technique. The execution of the test as well as the interpretation of the measurements are considered....

Phased Simulation of a Tunnel Boring process in Soft Soil

The advancement of a tunnel boring machine in the ground has been modelled<br/>using a phased excavation scheme, including the slurry support at the shield face, the conicity of the shield and the grouting at the shield tail. A comparison is made with field measurements obtained at the Second Heinenoord Tunnel. Also calculations are made...

Tunnel Face Stability & New CPT Applications

Nearly all tunnels bored in soft soils have encountered problems with the stability of the tunnel face. In several cases these problems led to an extended stand-still of the boring process. A better understanding of the face stability, and of the soil conditions around the tunnel boring machine, can reduce the risks during boring, and can avoid...

Appraisal of stickiness of natural clays from laboratory tests

Excavation of clayey soils by mechanical tools is often hindered by the stickiness of the clay on metal parts. Hindrance may occur at the cutting tool itself, or during the subsequent transport of the soil through the excavation system. The effects of stickiness were also experienced in a recent tunnel boring project carried out in The...

Face Stability Calculation for a Slurry Shield in Heterogeneous Soft Soils

The minimal support pressure needed at the tunnel face can be calculated using a wedge stability analysis. Current methods have been presented only for a homogeneous soil at the tunnel face. This Paper investigates the influence of heterogenity of the soil on the angle of slip and the minimal support pressure. It is found that the influence of...

Horizontal Cone Penetration Testing

In order to find the relationship between the cone resistances measured in horizontally and vertically aligned cone penetration tests, a test series has been performed in a 2 m. diameter rigid wall calibration chamber using a 36 mm. cone. This calibration chamber contains an unsaturated uniform sand, which can be prepared at different densities....