Geotechnical Investigation - Escoumins Harbour - Anse Aux Basques

Escoumins Harbour – Anse aux Basques

GEOTECHNICAL INVESTIGATION

1 MANDATE, OBJECTIVES, CONTEXT AND TESTS TO BE PERFORMED

1.1 Mandate

The mandate will consist of carrying out a drilling campaign in the area of the current floating docks. The contract will require drilling from a barge. Eight (8) boreholes are required and will be numbered F-01 to F-08 (see figure). If a slope is noticed between the front and rear boreholes, the 2 additional boreholes F09 and F10 must be added, based on the rate on the schedule.

Drillings F04 F06 and F07 will have to reach a depth of 2 m in bedrock. If the rock is of poor quality (very fractured – RQD less than 30%), it will be necessary to extend the drilling until an RQD of 50% is obtained, for a maximum of an additional 1.5 m, and promptly notify the Departmental Representative.

All field work shall be directly supervised by an intermediate geotechnical engineer.

1.2Context of survey

The Department of Fisheries and Oceans plans to build a wharf in the area of the current gangway. The following options are being considered:

1- Wooden crib dock with a dimension of approximately 13m X 30m ±;

2- Wharf with Berlin wall facade;

3- Wharf on piles with rock sockets

Option 1 - It is known that the rock in the area has a significant slope based on the plans of the existing structures and the surrounding topography. It is therefore important that the boreholes provide information on the slope of bedrock and that the study presents recommendations in relation to the stability of a timber crib and the bearing capacity of the soil in place and the anticipated settlements, if applicable. Recommendations are also expected on the suitability of the soils in place to withstand loads of a gravity structure, or if the ground must be excavated before setting up the cribs.

Option 2 – It is also required to provide recommendations related to the construction of a Berlin wall wharf. This study should therefore include rock sampling to determine the parameters required to design rock sockets.

Recognized references of two (2) calculation methods must be proposed which include the resistance of shear forces and moments at the base of the piles. The calculation methods must be presented in the report.

It is also requested to provide a calculation method and the recommended parameters for the design of rock anchors to take up the lateral thrust of the soil. For parameters and calculations, include clear explanations related to safety factors and weighting.

Finally, include an procedure with testing procedure that will be applied on site during the implementation of the works. This procedure will be included in the contractual documents and will allow quality control to be carried out during construction of sockets and tie rods.

The calculation methods must be determined and accepted by the Departmental Representative, prior to the field work.

Option 3 - For the option with piles, the parameters and recommendations must also be provided for the calculation of sockets in bedrock for the bearing of lateral and tensile loads. As for option 2, references of two (2) calculation methods must be provided.