Rocks Classification to Age - Report Example

Rocks Classification to Age Name of the student Name of the Institution Date of submission Part B Introduction The magnitude of the earthquake and its potential impact can be established by investigating the nature of rock strata in its totality. This study can also be very helpful for engineers who construct the bridge as it will help in establishing the suitability of the site. Cross sectional of the rock will help in giving more insights on the rock structure (Price 2015). The vertical cutting of rock structure is what is called cross sectional and it shows various layers of the rock from bottom to top. The arrangement of the rocks in strata from top to bottom is the relative age of the rock. If one is able to establish the age of two rock layers, then it is easier to know which rock is older than the other but is very difficult to understand how long the given layer is older than the other. This can be shown below; (Source: www.iris.edu/educate/animations accessed 1 October 2015) In using the principle of cross cutting relationship of the rocks, the rock intrusion is young since other rock must exist first before it can cut the across. Fault E from the figure is younger than other rocks it cuts through. C is older followed by B and A is the youngest rock. The same argument is supported by the principle of superposition which stresses the arrangement of sedimentary rocks. The sequence is the same and the occurrence of events can be illustrated as shown below . C>B>A>D D is the intrusion formed across the rock strata. Occurred, forming a layer of soil on top of layers A. Construction of cross section is easier with the availability of the geological maps as they give the information concerning the genera; stratigraphic columns which are important in the construction of the bridge. The earth vertical slices are enough to explain the major geological structure of a place. It helps engineers in interpreting major geological paths and depths. The stratigraphic columns are normally vertical representation of the width of the various formations in a given area (Price 2015). Once a vertical scale is chosen, each formation or unit is represented on the column at the thickness it crops out of the map area. The vertical cross section is given below; When constructing a bridge, these geological strata explanations are very important and can help in determining the vertical level of the bridge, establishing the direction of the water flow. Part C: Potential Bridge Sites In establishing the potential bridge sites, it is important to investigate and interrogate various issues concerned with geological issues and the site stability. An analysis of each site should be conducted and a comparison of the various sites should detail the strengths and weaknesses of each route. Issues South t North West East 1 Morphology type Cuts and fills bridge Tunnels fills Bridge and fills Cuts, tunnel fills 2 Condition of the topography Slope diversification along the hill Contains steep slope with many ridges on the slope It has many gullies and valise which are very smooth Smooth but with diversified slopes in downhill areas 3 Geological nature and structure High Low Normal High 4 Ground quality Loose materials with talus which are thick The quality of the Flysch is moderate There are materials that cover the surface Loose materials with talus which are thick with high flysch 5 Disturbance of tectonic structure High High Normal Normal for pindos rock masses 6 Uncertainty of the geological structure Yes No Yes Very limited 7 occurrence of old landslide Not all the time No No Yes 8 Riskiness of the landslide Moderate risk High risk No risk Low risk 9 Riskiness of the new landslides Cuts slope are very high consisting with the abutments bridge Limited to some extended and very much localized. Cuts slope are very high consisting with the abutments bridge Limited to some extended and very much localized and around bridge abutments 10 Instability resulting from underground water Yes No Yes No 11 Strengthening measures employs Very important for given density and strength and should be considered in the process Only restricted to the formation of the bridge Very important for given density and strength and should be considered in the process Only restricted to the formation of the bridge 12 Problem with the drainage system Low permeability consisting with the poor quality flysch in most of the areas and it creates uncertainties Low permeability consisting with the poor quality flysch in most of the areas and it creates uncertainties Not applicable Low permeability consisting with the poor quality flysch in most of the areas and it creates uncertainties 13 Follow up of drainage maintenance The system reliability must be emphasized to avoid degradation over time. This must be fixed with the follow up team and corrected in time The system reliability must be emphasized to avoid degradation over time. This must be fixed with the follow up team and corrected in time For some bridge foundation it requires this and not applicable for drainage, minor for support For some bridge foundation it requires this and not applicable for drainage, minor for support 14 Risk from geotechnical hazards during operation of the highway This exist locally as the rocks falls the steep slope. Remedial measures should be taken to avoid any occurrence of the risk This exist locally as the rocks falls the steep slope. Remedial measures should be taken to avoid any occurrence of the risk May exist locally due to rock falls from Steep slopes. These risks can be reduced to very low levels by appropriate remedial measures Uncertainty may exist over long sections of highway. This uncertainty is difficult to reduce to very low levels 15 Foundations of bridges Foundation sites close to unstable areas, often in weak flysch Foundation sites close to unstable areas, often in weak flysch Foundation sites close to unstable areas, often in weak flysch Foundation sites close to unstable areas, often in weak flysch 16 Environmental issues associated with geotechnical remedial works The possibility of encroachment on the river banks, structures that help in the maintaining the river bank, forest damage and re-vegetate in the process. The possibility of encroachment on the river banks, structures that help in the maintaining the river bank, forest damage and re-vegetate in the process. The impact is not as wide since construction of roads and bridges are mitigated. Muck from tunnels can be used to construct embankments for interchanges The impact is not as wide since construction of roads and bridges are mitigated. Muck from tunnels can be used to construct embankments for interchanges (Source: https://www.rocscience.com/documents/hoek/references/H2006.pdf accessed 1October 2015) Conclusion The magnitude of the earthquake and its potential impact can be established by investigating the nature of rock strata in its totality. In order to carryout comprehensive bridge design, the architecture must coordinate with the geologist to come up with these intensive geological facts and understand the ground under which the construction will take place. The comparison of the available sites is done so that the most suitable site is picked. In the above case, four sites were investigated and the various characteristics were listed in the above table to help in decision making. Bibliography Price, N. 2015 Fault and Joint Development in Brittle and Semi-Brittle Rock: The Commonwealth and International Library: Geology Division. Elsevier http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/24/Stratigraphy_Handout.pdf https://www.rocscience.com/documents/hoek/references/H2006.pdf Read More