Ground movement

Random vibrations, such as tho.se caused by an earthquake, cause shocks and ground movements and are termed seismic disturbances. Shocks and turbulence caused by a heavy sea, landslides and volcanic eruptions are also examples of shocks that may cause vibrations and result in tremors, not necessarily earthquakes. Nevertheless, they may require design considerations similar to those for an earthquake, depending upon the applieation (e.g. naval applications, hydro projects, dams and bridges). 

This identifies the part of the earth s surface directly above the hypocentre and where it produces the most severe ground movements. Away from the epicentre, the acceleration and the intensity of ground movements diminish. 

Greater depth of soil when there is a deep layer of soil, the intensity of the earthquake will reduce. The greater the distance from the focal point, the smaller will be ground movements. In such cases it is seen that the settlement of the soil below the structure may be negligible as it would have already settled by the time the shock reached the surface, and hence damage to the structure would be reduced. 

Soil does not provide as solid a base as rock. The strength of a foundation built on soil and its ability to withstand an earthquake will therefore depend upon the quality and depth of soils which may be formed of a number of soil layers of different stratifications and depths. Sandy soil or soil with sedimentary deposits, for instance, will have less strength and will provide a weaker base, as such soils may settle more during a ground movement. 

This is a response spectrum obtained during a test in a laboratory while exciting the shake table with ground movements as in the RRS. The test object is mounted on the shake table. The test object should respond normally during such movements. The test conditions (i.e. TRS) should closely overlap the required seismic conditions (i.e. RRS) of Figure 14.25. 

Now that it is possible to establish test facilities in a laboratory to simulate the time history of an earthquake seismic tests are conducted by creating the ground movements in the test object. Other methods, such as by analysis or by combined analysis and testing, are also available. Refer to IEEE 344 and lEC 60980 for more details. For this purpose a shake table, able to simulate the required seismic conditions (RRS) is developed on which the test object is mounted and its performance observed under the required shock conditions. Since it is not easy to create such conditions in a laboratory, there are only a few of these facilities available. The better equipped laboratories are in Japan, the USA, the UK, Greece, Germany, India and China. In India the Earthquake Engineering Department (EQD) of the University of Roorkee (UoR) is equipped with these facilities. 

Safe shutdown earthquake (SSE) test This is defined by the most severe earthquake that could occur, producing the maximum vibratory ground movements at the place of installation. Safety-related machines, devices and components should remain functional during an earthquake of this magnitude and maintain the safety and integrity of the plant until a safe... 

Passive test The test object is mounted on the shake table and subjected to both horizontal (X and Pj movements or one cumulative orthogonal horizontal and one vertical ground movement simultaneously. Accelerometers are mounted on the shake table to measure its movements and also on the test object at its most vulnerable points. These points may be identified by the manufacturer or the user to monitor the behaviour of the object in such locations. 

Resilient but rigid foundations such as by providing spring mounts or rubber pads for machines on the floor or for components and devices mounted on the machine so that they are able to absorb the vibrations, caused by resonance and quasi resonance effects, due to filtered out narrow band ground movements. The stiffness of the foundation (coefficient of the restoring force, k) may be chosen such that it would make the natural frequency of the equipment... 

Preliminary research has shown that Brillouin fiber-optic sensing systems provide a possible method to detect leaks and third-party intrusion on a pipeline over distances of 25 km or more. Their intrinsic response to both temperature and mechanical strain allows for the separation of these parameters and the detection of anomalies in the scan profiles. In addition, the same sensor could be integrated into the pipeline system to detect possible ground movement relative to fixed reference points. Limited test results on surface loads associated with the intrusion of vehicles and people on a pipeline have demonstrated the sensitivity of the system and its ability to discriminate loads at different soil depths. 

Bekendam, R. F. POTTGens, J. J. 1995. Ground movements over the coal mines of southern Limburg, the Netherlands, and their relation to rising mine waters. International Association of Hydrological Sciences, 234, 3-12. 

The detonation of the first 300-qt charge of NG1 resulted in ground movement recorded at a particle velocity of 2.5 in./sec. Air-entry intervals that existed after the first 100-qt shot were not apparent after the 300-qt shot however, new zones were opened to airflow. The injection capacity increased 500%. 

Chemically resistant masonry joints in clay pipe are rigid. Ground movement, such as settlement, can therefore break the pipe. For this reason it is important that all industrial waste lines be laid with continuous support. No matter what opinion others may have of the stability of the soil in the area where the pipe is to be laid, this writer has never seen any trench excavation, no matter how well prepared, that did not require adjustment to attain the suitable smooth surface and slope after the trenching operation had been completed. These adjustments require fill in some spots and further surface removal in others. In addition bell excavations are required to provide working room to make the joints. After the line is in service, heavy rains, flooding and even percolation of groundwater can cause soil movement above and around the pipe, and eventually, without uniform support, movement will take place that breaks the pipe. 

A-With concrete outer shell, we now have support for the brick, but note that the membrane is discontinuous at the bottom where it terminates at pipe edge. E-This is a typicai iniet design, with the entry pipe simpiy embedded in the waii, membrane brought to pipe edge and brick laid around the intruded pipe. Ground movement or expansion/contraction of the pipe can push or pull the pipe through the cavity in the concrete and cause the joint and membrane to be disrupted, and contained liquid to get back to the concrete. 

If the soils in the upper half of the tunnel cross-section and above the crown are groutable, very good ground movement control can be achieved by chemical grouting. 

The selection of a storage site is critical, since the criterion for container life (as currently designed) is variously estimated to be between 500 and 10,000 years. Obviously, the underground storage area must be totally free of ground movement during that same time interval. Predicting... 

This technology, obviously applied only to liquids, is used to place treated or untreated wastes into permeable injection zones that will not allow the contaminants access into potable water aquifers. The zones must be below any aquifers used for industrial and residential purposes, preferably highly saline, and isolated above and below by impermeable strata. Such geologic requirements, in areas immune to catastrophic ground movements, are generally not found within several thousand feet of ground surface. 

An electronics manufacturer had 400 transportation providers within its United States distribution network. Only 42 carriers delivered 98% of the volume. Of this select group. United Parcel Service was the primary carrier handling outbound ground movements, inbound shipments, ruid less-than-truckload freight to their customers or from suppliers. Due to either the physiceil product or package constraints, there were few exceptions that prevented them from having a minimum number of carriers within their distribution network. That network consisted of two plants (Syracuse, NY, euid Srilt Lake City, UT) and four distribution centers (Atlanta, GA, Chicago, IL, Dallas, TX, and San lose, CA). 

Ground movement parameters According to the filling mining technology data of neighboring... 

Mining Institute, 1981 China Coal Research Institute. The law of ground movement and overburden failure in coal mines. Beijing China Coal Industry Pubhshing... 

Earthquakes cause ground movement that causes destruction of rigid structures and liquefaction i.e. the sudden loss of strength of water saturated sediment. The ground movements also trigger mass movements like mudflows and landslides. 

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