We were requested to inspect the current conditiones of the excavation walls for the proposed residential houses
PNJ Engineering Inc. (PNJ) was requested by Mr. Baljit Ghariyal (Mr. Baljit) to inspect the current conditiones of the excavation walls for the proposed residential houses in Lots 1 & 2 at the above mentioned address. The inspection was to identify any excavation safety concerns with respect to trench wall slopes, potential cave-ins, adjoining property structures.
Upon arrival to site, PNJ met with Mr. Baljit and representatives of his team to discussed the site conditions and his concerns about results of a previous MOL inspection which needed to be rectified. He needed PNJ to outline the major areas of excavation deficiencies so that he may cut back the vertically excavated walls to correct non-conformances identified in a previous Ministry of Labour (MOL) audit.
PNJ informed Mr. Baljit that PNJ can only identify the most obvious safety concerns with the excavations in questions, the type of soil classification, and indicate which areas need to be slope back. However, rectification of the concerns is the responsibility of the Mr. Baljit's team and the various subcontractors.
Based on visual and tactical observations, PNJ is of the opinion that the soil type encountered in the excavation walls can be classified as a Type 2 soil. The existing ground conditions (frozen/frost) added a layer of difficulty in determining the exact type of soil. In addition, frozen ground can not be used a reasoning for vertical wall excavation stability. With time and warmer weather (thawing), the soil can be expected to cave in eventually. With Type 2 soil, all excavated material above a 1.2m (4') height needs to be sloped back at a Ratio of 1:1. This is to prevent any substantial amounts of material cave-in, avoid any worker injuries, and increase site access in case of emergencies.
PNJ visited each excavation of the above mentioned lots and identified the following characteristics:
The attached sketches provide a summary of the PNJ's observations. PNJ also inform Mr. Baljit of the observations made on site prior to leaving the site.