Civil Work in Plants & Refineries

This article is about Drilling and Installation of Monitoring Wells and Development  and focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website  www.paktechpoint.com  and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.

PLEASE SUBSCRIBE OUR PAKTECHPOINT YOUTUBE CHANNEL

 

Drilling and Installation of Monitoring Wells

Two (2) groundwater monitoring wells will be installed at locations specified. Methods and procedures for these works will be consistent with Aramco Standard SAES-A-115.
The procedure will be as follows:

• Prior to start of drilling, the locations of the wells will be confirmed with site representative. A starter pit will be advanced by hand tools to 1.2m prior to drilling, however, clearance of services will be the ultimate responsibility of contractor.
• The boreholes will be formed using a Rotary Wash Boring Technique to allow the installation of pipework of nominal 50mm internal, 63mm external diameter. A borehole log will be prepared for each location and an example borehole log is presented in Appendix A;
• Following completion of the borehole a 50-mm diameter UPVC casing and slotted sections of pipework will be installed down to the bottom of the hole. The screened section will be designed to straddle the resting water table so as to allow floating products (oils) to enter the well;
• After the 50-mm diameter uPV pipes are installed in the borehole, a filter pack of washed sand or pea size gravel (2mm to 4.75mm) will be poured into the borehole annulus. A 0.3m thick cushion will be poured between the bottom of the casing pipe. The filter pack will be poured from the bottom of the borehole to a depth approximately 0. ?Om above the top of screened (slotted) section.

Please read also: High strength, non shrink cementitious construction grout -CIVIL

• The level of filter pack will be checked by using a depth tape during the emplacement until there is no observable drop in the level of the filter material. The filter pack will be topped off to the desired depth and the volume of filter pack poured and the annular volume will be compared to verify proper emplacement of filter pack. In general two bags of filter pack (with a 50 kg mass each) filled about 1.5m height of the annular space between the HOPE (with 63mm OD) and the hole size. The density of the sand is 1.6 Mg/m3 and therefore the effective diameter of the hole is about 230mm.
• Sand/bentonite pelleUball seal will be poured immediately above the filter as the lower part of the sanitary seal to about 1.4 meters above the slotted section. The level of the top of the bentonite seal will be checked by depth tape. Adequate time for hydration of the bentonite pellets will be allowed before sealing the remaining annulus.
• Cement with approximately 5% bentonite mixed with in-situ soil will be used to complete the upper seal. The cement mixture will be tremied from the top of the bentonite to the ground surface.
• Locking, above ground well covers with concrete pads set to a grade will be installed at each well location (PVC casing pipe and four ‘protection’ or ‘guard’ posts) to minimize the potential .

An example of as built construction details of each monitoring well is shown here

Notes: 

1. Slottecl and blank PVC pipes are flush threaded.
2. Crash barriers are ollernately painted with yellow and black stripes.
3. Groundwater level and subsurface conditions shown above were based on Well Log of
4. Well construction based on the subsurface conditions encountered during drilling and sampling of boreholes.

Read more

This article is about High strength, non shrink cementitious construction grout – CIVIL and focusing to the engineers, technicians and supervisors. You will find lot of documents related to this article. Just navigate our website  www.paktechpoint.com  and find more articles. Please! Do not forget to subscribe our You tube channel also. Thanks in Advance.

PLEASE SUBSCRIBE OUR PAKTECHPOINT YOUTUBE CHANNEL

High strength, non shrink cementitious construction grout

Shrinkage compensated, cementitious grouts for use in bedding, grouting & precision bearing operations.

1. FOUNDATION PREPARATION:

1 . Preparation of the concrete surface to which the grout will bond should be carried out before the base plate is installed.
2 . Prepare the concrete surface using a chipping hammer, grit blasting or high pressure water jetting, to leave a roughly textured, clean surface, free from all forms of contamination. Bush hammering or similar method which can fracture
leave it in place is not permitted.
3. Preparation should cover the full extent of the surface which is intended to be in contact with grout.
4. Where it is indicated that bolts ere to be anchored within the grout. bolt pocket formers should be shaped to form cone, helping to ensure stresses that build up when the bolts are tightened are transmitted to the foundation.
5. Bolt pocket former-s should be made from materials that are easy to remove, but leave a rough concrete surface texture when stripped.
6. All surfaces and bolt pockets to receive grout must be clean and free of oil, dust,dirt, paint and residual curing compound .
7. All base plates, holding down bolts etc., are to be free of rust, oil, dirt or contaminants that could impair bond.

FORM WORK

1 . Before fixing formwork, ensure the foundation area and bolt holes are clean.
2. Formwork fitted around the base plate to contain the grout must be as watertight as is practical, to prevent grout loss.
3. The top of the formwork should be a minimum of 2.5 cm above the underside of the base plate.

4. For large base plate pours or when the gap between base plate and foundation concrete is of less than 2.5 cm depth, the formwork should be higher to allow a pressure head to build up.
5. On the pouring side, which should be the shortest distance across the base plate, a ‘hopper’ should be constructed to allow a pressure head sufficient to enable grout to flow to the full width of the pour. Th e form should be fixed with the top
sloping away from the base plate at a 45c angle to form a slope down which the grout can be poured.
6. The formwork should be fixed to allow easy stripping without causing damage or stress to the grout. if the formwork is to b e removed when the grout is still green.
7. If grout is to be pumped under pressure , formwork should be constructed to withstand the additional localised pressure .

Read more