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应用 本页显示了不同项目中地构仪器应用的选择。 请向下拖动页面，或从下面列表中选择一种应用范围： Braced ExcavationsThe design of projects such as these is based largely on past experience, and a monitoring program may not be necessary, provided that the design is very conservative, there is sufficient previous experience in similar situations and that the consequences of poor performance will not be severe. Outside of these conditions, a monitoring program will normally be required, to check that the excavation is stable and that nearby structures and utilities are not adversely affected. The monitoring may apply to the wall and bracing, the ground beneath and adjacent to the excavation or nearby structures and utilities.
Drilled Shafts and Bored PilesDrilled shafts (or drilled piers, caissons, drilled piles, bored piles, drilled caissons or cast-in-place piles) are made by drilling a hole, reinforcing it, and filling it with concrete. Design and performance considerations are, as with driven piles, largely to do with the load-movement relationships.
Driven PilesPiles can be deformed during driving, especially if driven to bedrock, or certain types of pile can cause large displacements, affecting pore-water pressure in surrounding soil and therefore neighbouring piles or general site stability. Instrumentation can be used to measure the effects of pile driving and thus help with planning this aspect of the project. Static load tests are usually carried out, either during the design phase or at the beginning of construction.
Embankments on soft ground (other than water-retaining)In the design and construction of embankments on soft ground, however "conservative" the soil parameters are, there is always an element of uncertainty. Instrumentation therefore has a significant role in the verification and, if needed, modification of the design and construction technique. Instrumentation is primarily used to monitor the process of consolidation and to determine whether or not the embankment is stable. It may occasionally be considered necessary to build a test embankment; in this case, instrumentation will play a vital role in evaluating the performance of the test model.
Embankment DamsIncluding earthfill dams of various types, rockfill dams with impervious earth cores and rockfill dams with upstream concrete or asphaltic concrete facings. The primary function of instrumentation in embankment dam construction and operation is to study whether or not the dam is behaving according to design predictions. These can either involve special conditions or uncommon design features, or simply be related to general behaviour. It should be noted that the instruments themselves can be the cause of problems occurring. This is generally where compaction has been imperfect, due to the presence of vertical pipes, tubes or cables as filling was in progress. (The general role of instrumentation in embankment dams is described by the International Commission on Large Dams (ICOLD).
Further monitoring techniques may also be advisable which are outside
the scope of Geotechnical Instrumentation, e.g. Precipitation Gauges,
Satellite-based distance measuring systems, Strong Motion Accelerographs,
Microseismographs and so on. Excavated and Natural SlopesWith excavated or natural slopes, the main concern is always the stability of the slope. The causes of instability are different for soil and rock. In soil, stability is a factor of the ratio between the available shearing resistance along a potential failure surface and the shear stress on the surface. In rock, failures usually occur as a result of sliding or separation along discontinuities in the rock, which contain water under pressure. Use of instrumentation can be divided into two phases - analysis of the ground prior to excavation and stability monitoring during excavation. The analysis prior to excavation will consists of, for example, geological surveying or installation of piezometers to monitor ground water pressure. For monitoring during excavation, attention should be paid to monitoring surface and sub-surface deformation and groundwater pressure
Underground ExcavationsThese may include tunnels in soil or rock, subway stations, underground nuclear waste repositories and mines. As with excavated slopes, the factors affecting stability vary depending on whether the excavation is in soil, clay or rock. For soil and clay, stability is related to shear strength ratios; for rock, it depends on discontinuities containing water under pressure. Full-scale instrumented test sections can be of great benefit in helping to determine design adequacy and economy, especially where the following four conditions obtain:
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