February 05, 2020
Vibrating Wire Piezometer is installed in a borehole using a fully grouted method. Using a traditional method involves the placement of sand pockets surrounding the piezometers, grout columns, and bentonite seals to separate piezometers at different levels. It is a slow and complicated process which also poses a great risk of unintended communication between piezometers.
Vibrating Wire Piezometer is designed to measure pore water pressure in the soil, earth/rock-fill foundations, and concrete structures.
Measurement of pore water pressure is used to detect the level and flow pattern of groundwater. It is also used to determine the flow pattern of water in earth/rock fill & concrete dams and the load-bearing capacity of soil or rock.
The vibrating wire piezometer installation procedure requires complete knowledge and assistance. Let us see how it is installed in a borehole. Before diving into that, we recommend you to go through the How Is Vibrating Wire Piezometer Installation Done?
Once you have prepared the piezometer for installation, you can proceed further.
Vibrating Wire Piezometer is installed in a borehole using a fully grouted method. Using a traditional method involves the placement of sand pockets surrounding the piezometers, grout columns, and bentonite seals to separate piezometers at different levels. It is a slow and complicated process which also poses a great risk of unintended communication between piezometers.On the other hand, the fully grouted method is quick and simple, resulting in excellent zone isolation.Vibrating Wire Piezometer requires a very little volume of water to read a change in pore water pressure, thus resulting in a fast response time.
NOTE: Encardio Rite Model EPP-30V is recommended for long term monitoring. A smaller diameter borehole can be drilled for EPP-40V as its outer diameter is 19mm.
Also Read: Vibrating Wire Piezometer – Types and Operating Principle
NOTE: Make sure to prepare the grout mix in an adequate amount so that the continuous grouting of the borehole can be carried without choking of the borehole and loss of instrumentation.
NOTE: Before lowering the piezometer in the borehole, record an initial reading and temperature with EDI-51V for a permanent record. This will form the zero reading for the piezometer. Also, note the barometric pressure at the time of taking an initial reading.
Also Read: What Are The Different Types Of Piezometers?
NOTE: It is advised to keep the maximum discharge head capacity of the grouting pump (Trash Pump) higher than the maximum depth of the borehole. If no details are available, the suggested grout pump is as follows:
Model KTH-80X-BABMake Keshin Ltd.Mix Discharge head 27 mDelivery Volume 1340 l/min
NOTE: Specially treated piezometers are used for saline water applications. The stainless steel diaphragm is protected with a thin layer (around 1 mm) of GE Silicones compound TSE 399. The remaining exposed cylindrical surface of the piezometer stainless steel body should be wrapped by a saline resistant tape like “33 super PVC 3M tape”. Particular care should be taken to cover the joint between the piezometer and the cable joint housing.
NOTE: At certain locations like earth/rockfill or concrete dams, it is convenient not to have the junction box and route one continuous cable from the sensor to the observation room. In such a case the platform (clause 4.3.13) is not made.
NOTE: Make a note of the elevation at which the piezometer is installed for future correlation of data and its analysis.
Here we come to an end of the vibrating wire piezometer installation procedure in a borehole. We hope you might have found this useful. If you have any questions or suggestions, feel free to drop them in the comments below.
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