1. INTRODUCTION
Rock mechanics is a discipline that uses the principles of mechanics to describe the behaviour of rock in different engineering scale level. Usually for engineering projects (slopes, tunnels and foundations), the scale ranges from a few tens to a few hundred meters. At engineering scale, rock is said to be inhomogeneous, discontinuities, anisotropic and non-linearly elastic. Besides that, rock mechanics also deals with the response of rock when the current boundary condition is disturbed; for instance, excavation of a tunnel in the ground, the in-situ stress of the rock is disturbed.
In this advanced rock mechanics module, a few major rock mechanics topics had been discussed; from the basic fundamental knowledge of the natural
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Therefore, in this report, the knowledge gained in this module are summarized and arranged into several sections. Firstly, a brief introduction about the background and the formation of rock will be discussed in Section 2. The formation process of three different categories of rocks is clearly illustrated into a diagram- the rock cycle. Secondly, in different engineering scale, rock can be considered as continuous (intact rock) and discontinuous (rock mass). In general, rock is a discontinuous medium because there is existence of various type of discontinuities. Rock mass and rock discontinuities especially rock joints are studied. The rock behaviors are usually governed by the properties of rock mass and rock joints. Therefore, several classification schemes that are used to estimate the rock mass properties as well as the geometrical, …show more content…
Igneous rock is formed when molten rock (magma) cools and solidifies, with or without crystallization. Igneous rock is then further classified into intrusive and extrusive; this phenomenon will affect the grain texture of the rocks. Intrusive igneous rock is rock that formed below the Earth surface whereas extrusive igneous rock is erupted onto the surface, hence this leads to the formation of coarse-grained and fine-grained rocks respectively. Sedimentary rock is formed from several ways; (i) the deposition of the weathered remains of the other rocks, (ii) the deposition of the results of biogenic activity, and (iii) the precipitation of solution. As for metamorphic rock, it is the formation of new rock from the transformation of an existing rock through metamorphism, i.e. the process in which the rock is subjected high heat and pressure. In comparison between the three types of rocks; igneous, sedimentary and metamorphic rocks, sedimentary rocks have a lower material strength than igneous and metamorphic rocks. This is due to the texture of the rock itself. In another words, the grains of sedimentary rocks are usually clastic which means that the
...e morphed it into the quartzite that is seen surrounding the butte (4). Rocks that undergo this process are called metamorphic rock, which is the same as the rock seen years ago by dinosaurs and other extinct creatures. The quartzite rocks were formerly seafloor sediment that was forced upwards, and then surrounded by lava basalt flows. Once erupted through fissures and floods through out most of the area, lava flow eventually created enough basalt to form a thickness of about 1.8 kilometers (1). All of this basalt flow eventually led to the covering of most mountains, leaving the buttes uncovered. The igneous lava flows and loess is reasons that the Palouse consists of such sprawling hills, and rich soil for farming (2). In result of the lava flows, the Precambrian rock Quartzite was formed. And lastly covered by the glacial loess, which were carried by the wind.
This rock type could prove dangerous, being soft and with little solidness in its structure. Therefore placing the protection over the rock cliffs was a very well thought and planned engineering
Shown in the picture above is volcanic extrusive igneous rock known as andesite. They were imported here to Laguna Beach to help minimize erosion (Merton Hill, p. 10-11). Extrusive Igneous rocks are formed on Earths surface due to lava quickly cooling or mixing with different materials such as ash or cinders from an eruption. There are two different types of extrusive igneous rocks; Plutonic and Volcanic. Andesite is known for being gray in color and being made up of very coarse grainy textures, which make it much harder to break down than sedimentary rocks. Unlike loose gravel and other sediments igneous rocks are known for being able to slow down seismic waves from earthquakes which cause less damage to surface structures.
Quartzite is a non-foliated metamorphic rock. This rock is intrusive and forms when exposed to extreme amounts of heat and pressure. Over a billion years ago, there was an ocean where Kamiak Butte is. This ocean floor was made of sand, as time went on oceans receded and the exposed sand underwent processes that turned it into sandstone – or as we learned in class the process of lithification. Years later, this sandstone would morph into the quartzite that is present now.2
One of the first people to study the xenoliths at El Joyazo was Zeck (1970); Zeck hypothesised that the xenoliths and dacitic lava of El Joyazo were derived syn-genetically from a semi-pelitic rock through anatexis. The protolith rock was thought to be separated into anatectic restites, represented by Al-rich xenoliths, and anatectic melt, represented by the dacitic lavas. The xenoliths were classified into three types: (1) almandine-biotite-sillimanite gneiss, (2) quartz-cordierite gneiss and (3) spinel-cordierite rock. Types 1 & 2 were interpreted as restite material as their structure corresponded to that of migmatitic restite, and type 3 as re-crystallised restite. It was suggested that this re-crystallisation would have taken place after that anatexis that produced types 1 & 2. Zeck described the lava, based on chemical composition, as an almandine bearing biotite-cordierite-labradorite rhyodacite. The xenoliths were described as well rounded fragments up to 40cm in diameter. The xenoliths were said to show a well developed foliation defined by biotite and sillimanite, with the exception of the spinel-cordierite rock, which exhibited a granoblastic texture. It was also noted that quartz is almost completely absent from these rocks with the exception of small, rare armoured relicts.
and Metamorphic rocks can be found. There are also a lot of crusted plates, and violent
Understanding the plate tectonics theory is very important, especially when investigating natural disasters like earthquakes, and volcanic eruptions. It is also gives scientists the ability to understand how mountains were formed between two tectonic plates. There are three types of interactions between plate boundaries: convergent, divergent and transform. Looking back at the history of these three different interactions, earthquakes, like the one in Haiti, volcanic eruptions, like at Mount St. Helens, and the creation of mountain belts, like the Mid-Atlantic Oceanic ridge, gives information on future consequences of tectonic movement, and what can happen when the plates interact with each other.
Riley, C.M. "Lahars." Geological and Mining Engineering Sciences. Michigan Tech. Web. 6 Feb. 2010. .
Magma is a hot liquid made of melted minerals. Minerals can form crystals when they are cool. Igneous rock can form underground, where the magma cools. slowly. Or, igneous rock can form above ground, where the magma cools.
Different rock types lead to different geological construction. According to different types of geological construction, different areas and regions have their own characteristics and functions for land use.
The plate tectonic theory is a theory that geologists use to help explain the Earth’s surface processes and events. It explains that the sliding of these plates are either away from each other, sliding past each other, or sliding into each other and causing one of the plates to slide beneath the other. There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries. A divergent boundary occurs when two tectonic plates move away from each other. Magma then flows up from the mantle to fill in the space between the plates, forming a raised ridge called a mid-ocean ridge. The magma also spreads in the exterior, forming new ocean floor and new oceanic crust. A convergent boundary occurs when two plates
There are a number of technical challenges that must be overcome to advance the concept of in-situ borehole extraction of non-soluble tabular resources to a commercially viable stage. One of the most important challenges is a technical understanding between cavity formation and stability for a given set of operating characteristics and geomechanical rock properties. The first step is to find a numerical code that is more user friendly and also can yield dependable results. Itasca Flac2D code was selected for this ongoing research. The main objective of this research was to verify if a widely employed 2-dimensional modeling software package (ItascaFlac2D) had sufficient accuracy to perform a stress analysis within a borehole mining system as part of a predictive design protocol. To achieve this objective, data derived from an empiric field study was modeled using Flac2D, and the results were compared to those obtained from a case study that used a three dimensional model (Flac3D). The case study data used in this chapter was obtained from a subsidence study prepared by Barr Engineering Company for Cooperative Mineral Resources (CMR) [1]. CMR sought to collect samples from two enriched manganese zones within an oxidized iron-formation at a site located near Emily, Minnesota. Through bulk sampling, CMR intended to evaluate the potential of using a small scale Borehole Mining (BHM) system that employed waterjet technology. CMR believed that the enriched manganese zones in the resource were suitable to BHM excavation methods and as part of the technical feasibility of the project, a subsidence study was performed by Barr Engineering. One of the primary goals of this study was to determine if subsidence would occur under specific operating conditions and, if so, to develop a range of potential depth and the radial extents of the surface damage at the Project Area.
I begin my hike in comfortable clothes, a camelbak, flashlight and my ticket to view the caves. The first thing I see is the large rockslide above the visitor’s center. The rockslide is called talus slop. A talus slope describes a type of rockslide that is a loose debris piles. Talus slopes have mild to moderate rockslides as rocks slide down the pile. I was surprised when one such rock hit my head dead center.
Chemical Weathering is when water weakens the structure of the rock and Mechanical Weathering is where water seeps into the rock face causing fragments of rock to break off.
The natural rock gardening ideas are given by the nature. The rocky yards are covered with greenery in order to beautify the area. In the rock gardens the stones, stumps, logs are not removed like the other garden types but are the vital elements of these gardens. Isolated boulders work as the miniature rock gardens which serve as ornament and containers. The natural rock gardens include various elements such as wood steps, path lined with rocks, boulders, variety of plants and rest atop pebbles which give the garden practical and vivid look. The rock garden plants are ferns, spruce evergreen and fir. The functional uses are less important than the aesthetic beauty of the rock gardens. The balance of textures and colors of the plants make the rock gardens visual...