Abstract

Under hösten 2013 offentliggjorde den svenska regeringen att man vill investera i att bygga ut Stockholms tunnelbana. Denna utbyggnad innefattar nio nya stationer, Sofia på Södermalm är en av dessa stationer. På grund av platsens förutsättningar kommer stationen bli en av de djupaste i världen. Detta förslag utnyttjar dessa förutsättningar för att sammankoppla gatunivån med den underjordiska perrongen och ger den vardagliga upplevelsen av rymd, atmosfär, ljus och tomrum en central position. Förslaget innefattar ett hundra meter djupt schakt, två hisschakt, ett publikt torg park och tunnelbaneperrong.  During the autumn of 2013 the Swedish government announced that they intend to invest in expanding the Stockholm Metro. The expansion includes nine new stations; Sofia on Södermalm is one of them. The conditions of the site make the station to one of the deepest in the world. This proposal makes use of these conditions to connect the street level and the underground platform level and give the everyday experience of space, atmosphere, light and void a central position. The proposal comprises a hundred meters deep shaft, two elevator shafts, a public square park and train platform. 

Abstract

The Cañaveral shopping center is located on a low slope formed by recent alluvial deposits of low consistency, supported on sedimentary rock of the Girón formation, which is found at depths that change abruptly between one and twelve meters in short distances, influenced by the presence of a geological fault line and processes of erosion and weathering by subway water currents. Considering that the loads on the foundation are of great magnitude, it is necessary to build about 100 deep caisson foundations to reach the rock. However, performing a borehole on each one of them represented a very high cost and long execution times that would generate discomfort in the operation of the warehouse. Therefore, an alternative was proposed to determine the depth levels of the rock through different geophysical tests of seismic lines and electrical tomography and try to calibrate the results through the correlation of some boreholes. During the execution and data processing phase of the geophysical tests, difficulties were encountered due to the level of environmental noise and the obtaining of the wave records, given the variability of the rock levels and even the effect that in some sectors of the study area the rock is very sub-surface. In conclusion, it was possible to identify the strengths and weaknesses of each of the exploration methods and generate a 3D map of the depths of the rock levels that served as input for the design and budget of the foundations, which were verified by constant supervision during construction and thus be able to determine the error percentages, as well as to present recommendations for future works where it is intended to use this type of techniques

Abstract

It is known that the initially proposed circular/spherical rigid particle models are not able to match the ratio of the compressive strength to tensile strength that occurs in rock and the predicted macroscopic friction angle was much lower than the known hard rock experimental values. For this reason, several enhancements have been proposed to address these issues, namely the use of a clumped particle logic, the increase of the number of contacts per particle, the adoption of polygonal/polyhedral grain structures. A flexible 2D DEM based particle model that allows deformable particles to interact in a simplified away is presented. The flexible particle model is tested using biaxial tests and Brazilian tests. The results obtained are compared with those obtained with a rigid particle model with similar contact strength properties and with a flexible particle model, where the flexibility is due to the inner discretization of the grain with smaller particles. The results show that the proposed flexible particle model can predict a behaviour similar to a flexible particle model through inner particle discretization that is more computationally demanding. It is also shown that when compared with a rigid model, the flexible model predicts more reasonable indirect tensile strength to direct tensile strength ratio and requires a smaller value of contact fracture energy to give a good agreement with known experimental data.