Vibrating Wire Piezoemeter
Merek : Slope Indicator - USA
Kategori : Alat Ukur Tahanan Tanah, Alat Laboratorium
Typical applications for piezometric are:
Pore water pressures to monitoring • determine safe rates of fill or excavation.
Monitoring of pore water pressures to evaluate slope stability.
Monitoring systems used for dewatering excavations.
Monitoring of ground improvement systems, such as vertical drains and sand drains.
Pore pressures monitoring to check the performance of sprawling earthfill dam.completion dams and embankments.
Pore pressures to monitoringcheck containment systems at landfills and tailings dams.
Types of Piezometric:
1. the Standpipe Piezometric:
The standpipe piezometer is the most basic of piezometer types. It consists of a filter tip joined to a riser pipe. Water flow from the surrounding soil into the standpipe. Readings are obtained with a water level indicator.
Advantages: Simple, reliable, not electrical, no calibrated components.
Limitations: Accuracy depends on the skill of operator; reading requires a man on site; remote reading is not possible; slower to show changes in pore-water pressure.
2. the Vibrating Wire Piezometric:
The vibrating wire piezometer is the most commonly deployed piezometer and is suitable for almost all applications. It consists of a vibrating wire pressure transducer and signal cable. It can be installed in a borehole, embedded in the fill, or suspended in a standpipe. Readings are obtained with a portable readout or a data logger.
Advantages: Easy to read, very accurate; good response time in all soils; easy to automate; reliable remote readings.
Limitations: Must be protected from electrical transients.
3. Multi-level Vibrating Wire Piezometer:
The multi-level VW piezometer system is used to monitor pore-water pressure at multiple zones in a borehole. It consists of a number of VW piezometric in special housings, signal cable, a grout fittings, and some user supplied components (mainly PVC pipe). The system is grouted into a borehole. Readings are obtained with a portable readout or a data logger.
Advantages: Solves or avoids most of the problems with traditional multi-level piezometer installations.
Limitations: Same u.s. VW piezometric.
4. Vented Vibrating Wire Pressure Transducers:
The vibrating wire piezometer consists of a vibrating wire pressure transducer, a vented signal cable, and a desiccant chamber. It is designed for monitoriNG water levels in wells, stilling basins, and wiers. Readings are obtained with a portable readout or a data logger.
Advantages: Easy to read, accurate, and can be connected to data loggers. Requires no barometric pressure compensation.
Limitations: Electrical noise from a pump in the same well can interfere with operation.
5. Titanium Pressure Transducer:
The titanium pressure transducer is a 4-20mA device that is compatible with industrial data loggers.It is use for monitoring water levels in pumping wells and for monitoring of pore-water pressure in environments that would corrode stainless steel.
Advantages: Suitable for dynamic measurements, easy to read, highly resistant to electrical noise.
Limitations: 4-20mA circuits require more power so are less suitable for battery-operation. Long term stability may not be good enough for some applications.
6. Pneumatic Piezometric:
The pneumatic piezometer operates by gas pressure. It consists of a pneumatic pressure transducer and pneumatic tubing. It can be installed in a borehole, embedded in the fill, or suspended in a standpipe. Readings are obtained with a pneumatic indicator.
Advantages of Vibrating Wire Piezometers
High Resolution: VW piezometers provide a resolution of 0.025% of full scale.
High Accuracy: Slope Indicator's automated, precision calibration system ensures that all VW piezometers meet or exceed their accuracy specifications.
Groutable: The VW piezometer can be directly grouted-in with a bentonite-cement grout. More information about the direct grout-in method can be found in the VW piezometer manual and in a technical note.
Rapid Response: VW piezometers offer rapid response to changes in pore water pressure, whether they are grouted in, pushed into cohesive soils, or embedded in a sand filter zone.
Reliable Signal Transmission: With properly shielded cable, signals from the VW piezometer can be transmitted long distances.
Temperature Measurement: All VW piezometers are equipped with a temperature sensor.
Kategori : Alat Ukur Tahanan Tanah
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