This paper presents a unique pumped hydro storage facility using the ocean as a lower reservoir, combined with solar photovoltaic to create consistent, clean power. This project will allow for large-scale renewable energy adoption in Chile. The country's Atacama Desert has one of the best solar resources of the world. Unfortunately, the electricity grid in that northern region has one of the highest carbon footprints in the world because almost all of the electricity generation comes from fossil fuel power plants. Nearly 90 % of the demand on that northern grid is from mining companies. Their operations' energy needs are high and constant - day and night, and as a result the mining companies will not assume the intermittency risk of renewable energy resources. Until now, solar and wind developers have only been able to offer intermittent solutions and, therefore, have been unable to sign major power purchase agreements.

The interaction between deep-seated landslides and infrastructure facilities is a topic of relevant interest in the rock mechanics literature. This paper discusses the case of deep-seated landslides reactivated during excavation of two large twin tunnels in Italy, with an overview of the geological, hydrogeological and geotechnical conditions. The efforts made in order to gain an understanding of the complexities involved and the necessary quantification of the stability problems during tunnel excavation are presented in each case. Two- and three-dimensional numerical modelling methods, used as a means to back-analyze the reactivated landslide and the interaction with the tunnels, are discussed. It is shown how modelling associated with advanced real-time monitoring may contribute to the understanding of the problems under study.

NFM Technologies has designed and delivered four 6.99 m-diameter Double Shield TBMs that are excavating the North West Rail Link project, an extension to the Sydney rapid transit network. The project is led by a consortium comprising Thiess, John Holland and Dragados, acting on behalf of the Government of New South Wales Transport Authority. Altogether, the TBMs will build 15 km of twin tunnels in rock that is mainly formed of abrasive sandstone. TBMs 1 and 2 bore the 9 km section between the Bella Vista and Cherrybrook stations, while the remaining 6 km from Cherrybrook to the Epping interchange are bored by TBMs 3 and 4.
In this paper, we focus on the achieved performance of the 4 TBMs after approximately 50% completion. We analyse their variations in terms of excavation speed and consumption of disc cutters against the geology and geotechnical characteristics along the tunnel route. We discuss the overall production data and specific aspects of this hard rock urban tunnel project.

Due to uncertainties in the ground model and the spread of geotechnical properties, prediction of the exact system behaviour of underground structures is difficult in many cases. In order to manage this problem, the so-called observational approach is often applied. Monitoring plays an important role to verify or falsify design assumptions, to adjust excavation and support measures to the actual conditions and to assess the stability of the system. For the management of the residual risk a geotechnical safety management plan is implemented. The OeGG has recently published a handbook summarizing the state of the art in tunnel monitoring and geotechnical safety management.

Geotechnical analysis for underground excavation design in complex tectonic environments requires an increased understanding and more rigorous consideration of the impact of healed or "intrablock" structure, such as veins, on rockmass behaviour. Intrablock structure occurs between blocks of rock defined and bounded by "interblock structure", the network of joints and other fractures conventionally considered in classic rockmass characterization, classification or rockmass property estimation. Discrete simulation of fractures has become a more commonplace model analysis technique for excavations in jointed rockmasses. Here too, however, special attention is required to simulate intrablock structure within the model. In particular, the selection and evolution of stiffness and strength values for the model discontinuity elements must follow a different logic than that adopted for fractures and true joints. A new concept to better represent the behaviour of intrablock structure in explicit numerical models is proposed and tested in this paper by means of finite element method (FEM) analysis and case study data from a 1, 200 m deep drift. This approach changes the stiffness and strength values of failed intrablock structural elements between pre-peak ("primary"), post-peak ("secondary"), and ultimate ("tertiary") states. The FEM models in the tertiary state match 96 % of overbreak patterns along the case drift, versus 80 % in primary state models. These findings suggest that the proposed method is a good option to more accurately model the influence of intrablock structure on rockmass behaviour.

Indurated clay formations are under consideration as potential host rock formations for the disposal of radioactive waste in several countries. The favourable features of such formations for deep geological repositories include an excellent hydraulic barrier function, high capacity for dissolved radionuclide retention and considerable self-sealing potential. The development of a brittle fracture network (excavation-induced damage zone, EDZ) around underground structures during construction and operation cannot however be avoided. To assess the impact of the EDZ on long-term safety of the repository, a detailed structural inventory of the fracture network and the relevant hydro-mechanical phenomena and processes during excavation and the subsequent operation phase is required. This then forms the geomechanical basis for the development of conceptual and numerical models of the EDZ. Here we present some empirical and experimental evidence from the Mont Terri Underground Research Laboratory (URL), summarizing the key phenomena and processes associated with the creation and evolution of an EDZ in the Opalinus Clay. In particular, the significance of rock mass anisotropy is highlighted, both as a likely origin for far-reaching pore fluid pressure changes and as a controlling factor in EDZ development during the excavation process.

As a potential host rock for deep geological disposal of radioactive waste, the Callovo-Oxfordian and Opalinus clay rocks have been extensively investigated in the laboratory with respect to deformation under various thermo-hydro-mechanical conditions: (1) stresses covering the range from the initial lithostatic state to redistributed levels after excavation, (2) humidity variations representing ventilation during operation of tunnels as well as water migration from the far-field and (3) heating from ambient temperature up to 100 °C and a subsequent cooling phase. For these highly consolidated clay rocks, a new concept is theoretically derived to explain the effective stress in the particle matrix and experimentally confirmed. The mechanical deformation of the clay rocks is determined by means of short- and long-term compression experiments on quasi water-saturated samples at ambient temperature. Reponses of the clay rocks to humidity changes are examined by drying and wetting the samples under different loading conditions. Thermal effects are studied by heating and cooling the stressed samples under drained and undrained conditions. The main findings are presented and discussed in this paper.

The paper describes the development of a geological and geotechnical model produced for the design of a hydro power plant and its large RCC (roller compacted concrete) dam. Various in situ and laboratory investigation methods and rock mass classification were introduced for the definition of subsurface parameters and rock mass parameters were derived for design purposes. The mechanical parameters of the rock masses were the basic input for different finite element models that were used in order to evaluate the interacting static system of foundations and structures. The insights gained from this work were used to implement appropriate amendments to the design of the hydropower plant.

Based on recent advances in modelling the post-yield behaviour of brittle rock, the authors have developed a calibrated inelastic model of the 7,910 level (2.4 km depth) at the Creighton Mine in Sudbury, Ontario, Canada using data collected from the monitoring of pillar dilatancy. While this calibrated model represents a state-of-the-art continuum approach for capturing the progressive development of yield and stresses in mine pillars, alternative state-of-practice approaches (elastic and perfectly plastic material models, for example) represent potentially acceptable options for practical application.
The purpose of this study is to examine the influence of constitutive model choice on stress paths throughout the pillar system at the mining level of interest. The strengths and limitations of various material models are compared and contrasted. Elastic models are shown to adequately represent the larger scale pillar system behaviour from a stress transfer perspective, whereas the state-of-art brittle modelling approach is shown to be ideal for understanding specific pillar-scale stresses and yield.

The Arlberg Tunnel: DSI supplies ground support products for Austria's longest road tunnel / Der Arlberg Tunnel: DSI liefert Stützmittel für Österreichs längsten Straßentunnel

Groundwater management for the construction of the metro in Copenhagen / Grundwassermanagement für Kopenhagener Metro-Bau
3D images from TBMs

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This work presents the results of experimental tests on full-scale one-bay, one-storey reinforced concrete (RC) frames, filled with non-load-bearing clay masonry walls. The infill walls were made with clay masonry units characterized by a high percentage of voids and low strength. Such ‘light’ infill walls have shown fragile behaviour during recent earthquakes, due to the combined effects of damage produced by out-of-plane seismic action, together with in-plane deformation of the RC frame.
In this context, various solutions to the problems involved in external reinforcement of ‘light’ infill walls, typically found in existing RC buildings but still used in common construction practice, have recently been developed. These solutions are: i) special lime-based plaster with geo-polymer binder; ii) bidirectional composite meshes applied with inorganic matrices, i.e., Textile Reinforced Mortars (TRM); iii) TRM improved by anchorage of the mesh to the RC frame.
For these construction elements, a special set-up for combined in-plane/out-of-plane cyclic testing, already used for other infill wall types at the University of Padova, was used. In particular, this work describes: a) materials and systems for strengthening infill walls; b) experimental results of infill walls under in-plane loads; c) effects of out-of-plane loads on previously in-plane damaged infill walls. The final aim was to achieve complete mechanical characterization of infill walls in both original and strengthened conditions, and to validate the effectiveness of the proposed strengthening systems.

As part of the EU project, INSYSME - INnovative SYStems for earthquake resistant Masonry Enclosures in reinforced concrete buildings - to optimise infill masonry the German project partners carried out an initial part of the project on flexural strength testing of high-tech clay block masonry in accordance with DIN EN 1052-2. In this a wide range of modern products was considered which at present is regulated in Germany by means of general building authority approvals. The test results show that the specifications for flexural tensile strength of high-tech clay block masonry in DIN EN 1996 are very conservative in most cases.

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The realistic modelling of seismically loaded infill masonry is a complicated task due to the complex interaction of the infill with the surrounding frame. Practical approaches, that take into consideration the non-linear behaviour of the infill and the frame, are especially lacking at the moment. Within the framework of the European project INSYSME (Innovative Systems for Earthquake Resistant Masonry Enclosures in R.C. Buildings [1]), the behaviour of infill masonry in reinforced concrete frames is being investigated experimentally to derive different strategies for the modelling of infill masonry. In addition, systems for the improvement of the seismic behaviour will be developed. In the following, some initial results of the different modelling strategies are presented.

A comparative environmental assessment study focusing on the stages of mortar production and carbonation through hardening has been conducted by the European Lime Association in collaboration with mortar producers from various EU countries on 17 formulations of mortars, renders and plasters. The results of the “cradle-to-gate” for mortar and renders indicated that: There are no significant differences between products with low and high lime contents and depending on the lime content in the products, the contribution of the hydrated lime to the different environmental indicators can range between 0 % and about 20 %. However, there are clear differences in the environmental footprints of gypsum or lime based plasters. Based on the plaster composition investigated in this study, it appears that lime based plasters have the lowest environmental footprint for some of the impacts (primary energy consumption, abiotic depletion and water eutrophication), whereas for the remaining indicators the gypsum based plasters have the lowest environmental footprint. Depending on the lime content in the plasters, the contribution of the hydrated lime to the different environmental indicators can vary in a wide range, i. e. between 0 and 40 %.
The differences in the environmental impacts of mortars, renders and plasters produced in integrated or non-integrated mortar plants are generally rather small The lime carbonation process lowers the overall carbon footprint during the first period of the use phase of the mortars in buildings. This impact shall be taken into account in holistic LCA studies. If not, this leads to a wrong interpretation of the environmental impact of the mortars.

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In this paper results of the experimental testing performed on brick masonry and earth block masonry are presented. The paper outlines the development of the testing procedures for two different types of anchors. For this purpose, two experimental campaigns of pull-out tests on masonry corner connections strengthened by metallic rod grouted were carried out. Experimental results proved that the implemented testing procedures are suitable to determine the most recurring failure modes of the anchor pins. Moreover, a procedure is proposed to estimate the capacity of grouted anchor pins based on experimental studies.

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The work of plastering and rendering masonry and concrete is covered by a huge range of standards and guidelines. The new publication “Guidelines for plastering and rendering masonry and concrete” presents a standard work, which clarifies the issues for designers and contractors alike.

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