Pre-Piling area study

As the Piling or foundation is rightfully taken as 1st key construction activity on the site, so it’s important that we understand our area of piling work before we get into the business. Knowing our work area is important in a sense that gives us many ideas about how we are going to work here, what are the likely challenges we can face here and what are the Prevention’s that we can adopt.

Your work area may welcome you in its different status. Some may welcome you as an empty land and some may welcome you as a recently demolished building. Below is the view that welcomed me very 1st when I entered to my work area back in Aug 2014.

site

Work site before the commencement of piling work

As we are going to start underground works, the Pilling, so for us it’s important to know what lies beneath this grass. We are lucky that design team was there much before us and they can provide us with the soil investigation report of the area. Soil investigation report is the one key document which takes us down into the ground as our tour guide and tells us about the hidden assets beneath. The document, Soil Investigation Report, is the authority on the matter as it’s the only document which has covered a wide range of tests to identify the soil strata and its variation within the site. 1 borehole is investigated for each 300 sqm whereas there are 3 minimum boreholes for each work site. You can further look into the prevailing code of practice for site investigation or Foundation works in your geographical region about the number of boreholes and depth of the each required. You can see here a spread of the boreholes within the site. All these boreholes were investigated to establish the soil strata and variation within the site.

Site Investigation Soil Piling Construction Foundation

Borehole distribution for Site investigation

A plot of the boreholes in terms of their depth and then the levels of similar soil types tell you how soil strata vary when traveling from one borehole to the other in a particular direction. As the Soil investigation report presents you all the bore logs (vertical profile at a borehole), you can take an area of your interest and take out the bore logs within that particular area and start matching their profiles. It will give you a complete understanding how soil strata vary from one particular point to the other within your selected area. It’s important to take note that such an investigation doesn’t reveal the complete variation of the strata but it presents it to a greater extent. More you increase the number of boreholes the more you can know the strata variation.

Borehole log Soil investigation Piling Foundation

Borehole log showing strata distribution

Imagine if you are piling in a site and your rig hit to an underground water or gas pipeline?

It’s important to have a study of the site if there is any public utility service passing through. Underground service detection report can present you all such items. If there is any underground service passing through your site, it’s important to arrange a proper diversion or protection of such utility service before working in that particular localized area.

Piling is a high vibration activity so it’s important to have a survey of buildings and roads nearby to assess and record the existing conditions. In Singapore, normally a professional is engaged to provide a Pre-Condition survey report and this report can be referred to in case if there any claim appear of damage caused by the construction or piling activity as your site.

underground services precon survey

Precon survey – Underground services verification and settlement around the site