Design optimization of TBM disc cutters for different geological conditions

A novel optimization methodology for the disc cutter designs of tunnel boring machines (TBM) was presented. To fully understand the characteristics and performance of TBM cutters, a comprehensive list of performance parameters were investigated, including maximum equivalent stress and strain, specific energy and wear life which were closely related to the cutting forces and profile geometry of the cutter rings. A systematic method was employed to evaluate an overall performance index by incorporating objectives at all possible geological conditions. The Multi-objective & Multi-geologic Conditions Optimization (MMCO) program was then developed, which combined the updating of finite element model, system evaluation, finite element solving, post-processing and optimization algorithm. Finally, the MMCO was used to optimize the TBM cutters used in a TBM tunnel project in China. The results show that the optimization significantly improves the working performances of the cutters under all geological conditions considered

Peculiarities of the underground mining of high-grade iron ores in anomalous geological conditions

This paper is dedicated to research into the geological peculiarities, shape of the ore body and the occurrence of the host rocks in the hanging wall of the Pivdenno-Bilozerske deposit , as well as their influence on the degrees and quality of high-grade iron ore extraction. It is noted that in the interval of 480 – 840 m depths, a decrease is observed in the stability of the natural and technogenic massif, which is caused by the increase in rock pressure with depth, the influence of blasting operations on the massif and the difference in geological conditions. This has led to the collapse of hanging wall rocks and backfill into the mined-out space of chambers in certain areas of the deposit, the dilution of the ore and deterioration of the operational state of the underground mine workings. Attention is focused on the causes and peculiarities of consequences of the collapse of the hanging wall rocks during ore mining, which reduce the technical and-economic indexes of the ore extraction from the chambers. A 3D-model of an ore deposit with complex structural framework has been developed, which makes it possible to visually observe in axonometric projection the geological peculiarities and the shape of the ore body. The parameters have been studied of mining chambers in the 640 – 740 m floor under different changing geological conditions of the ore deposit and hanging wall rocks occurrence – the northern, central and southern parts. The difference in the iron content in the mined ore relative to the initial iron content in the massif has been defined as an indicative criterion of the influence of changing conditions on the production quality. The reasons have been revealed which contribute to the collapse of the rocks and the subsequent decrease in the iron content of the mined ore in ore deposit areas dif- fering by their characteristics. It has been determined that within the central and half of the southern ore deposit parts with a length of 600 m, an anomalous geological zone is formed, the manifestation of which will be increased with the depth of mining. It was noted that within this zone, with the highest intensity and density of collapse of hanging wall rocks, the influence of decrease in the slope angle and change in the strike direction are of greatest priority, and such geological factors as a decrease in hardness, rock morphology, deposit thickness increase this influence significantly. To solve the problems of the hanging wall rocks’ stability, it is recommended to study the nature and direction of action of gravity forces on the stope chambers in the northern, central and southern parts, as well to search for scientific solutions in regard to changes in the geometric shapes of stope chambers and their spatial location, improving the order of reserves mining in terms of the ore deposit area, the rational order of breaking-out ore reserves in the chambers with changing mining and geological conditions of the fields’ development

Engineering geology maps of the UK

School and university students of geology, engineering geology and geotechnical engineering generally have less knowledge of engineering geological conditions than those who have had experience of hands-on research or practice. In the UK, the number of geology, geoscience and earth science departments has reduced over the past 25 years. Engineering geology has a very weak academic base and geology is taught less to civil engineering students than previously

The importance of proper evaluation of the geological conditions for the design of industrial floor subbase

Nowadays many problems concerning industrial floors or floors in shopping centres occurred when local geological characterization is not adequately considered by structural designers, material selection is not evaluated properly and in time for future stability, or consolidation of soft organic subsoil laid in active zone is not taken into account during design evaluation. Similar problems occur when flooding effects on subbase layers cause a new settlement of the upper floor structure. Generally speaking, majority of these symptoms of floor damage have their origin in underestimation of the geotechnical risk. At some locations, the selection of support structure and material type is not adequate due to lack of experience and in order to offer the lowest price as a contractor

Geological Conditions Affecting Dams in San Gabriel Canyon

In view of the different plans being considered for the building of high dams in San Gabriel Canyon a statement of the geological conditions as they affect impounding structures in that drainageway may be pertinent and of interest. The writer's examination of the canyon reveals that the geological conditions from its mouth to the forks are quite similar, differing only in minor details. The dominant rocks are gneiss and a variety of coarse-grained intrusive igneous rocks of the general nature of granites and diorites. Dikes of both acid and basic rocks are common. Quartz and calcite veins occur occasionally

Assessment of blasting operations effects during highway tunnel construction

Blasting operations are one of the fundamental parts of daily civil engineering. Drilling and blasting still remain the only possible ways of tunnelling in very adverse geological conditions. However, this method is a source of various disadvantages, the main one being tremors propagating through the geological environment which not only affect buildings, but also disturb the comfort of living in the vicinity of the source. Designing this procedure is mostly done using standardized empirical relations. This article shows the possibility of using a FEM technique in predicting blast effects. This approach is demonstrated in a simple case study on the impact of blasting operations on steel pipes