10 Works documentation
10.1 The following documents should be available on site:
- a geotechnical baseline report containing all the investigative data relevant to the establishment of a design for the grouting works;
- an organization chart which clearly defines the decision making responsibilities of the key personnel representing all concerned parties;
- a Method Statement which defines the objectives of the grouting work, details the procedures that will be employed to achieve that objective, and proposes measurable criteria that will be used to establish the attainment of the objective. The Method Statement will be agreed upon by the responsible parties as a basis for commencing the work and contains:
- a plan detailing all boreholes (plan view and sections), existing structures, geological formations, water levels, planned constructions and boundaries of treatment;
- a document detailing the types of grout, the envisaged quantities of grout to be injected per grout stage in each borehole, the sequence of injection, maximum pressures and the injection rates expected;
- documents concerned with monitoring on site, maintenance and further activities after handover of the grouting works.
10.2 The following documents should be produced on site:
- a daily record of observations concerning drilling and grouting;
- a monthly record indicating the daily progress and the grout consumption;
- a final report containing all pertinent technical and quantitative details;
- a handover report on completion of the works in which the concerned parties confirm the attainment of the acceptance criteria defined in the Method Statement.
10.3 The site reports shall mention:
- dates of activities;
- borehole (injection point) number and position, length, diameter, direction and inclination;
- names of drillers;
- drilling rig and method;
- type of drilling fluid;
- borehole equipment (e.g. casing, sleeve pipes, type of seal grout, etc.);
- special observations during drilling or installation of equipment (e.g. fluid loss, unexpected loss of seal grout);
- mixing and injection:
- grout compositions (types and mixing proportions) and characteristics;
- grout volumes injected into the ground (consumption), pressure and duration for each pass;
- interaction with other boreholes and observed leakage;
- any unusual incidents and observations;
- sampling of the grout being used;
- number of samples for laboratory;
- routine quality controls;
- names of personnel (and their qualification). These records shall form the basis of grouting control.
10.4 A record of the ground surface levels shall be kept when necessary.
10.5 The grouting results should be summarized by graphical means and by statistical means where appropriate (e.g. graphs of pressure against time).
10.6 Special events and decisions taken both during drilling and injection shall be recorded in field log books.
10.7 Grouting reports shall be prepared on site and signed by the responsible site engineer or his representative.