[en] The EDZ (Excavation Damaged Zone) is one of the issues in the evaluation of the long term safety concerning the underground rock surfaces of the final disposal facility. There have been various research and development tasks relating to the EDZ (among other items the EDZ300 Project) completed both before starting the excavation of the ONKALO underground facility and during the construction work. The EDZ09 Project was established to improve the drill and blast excavation method to control the EDZ and to verify the feasibility of Ground Penetrating Radar as a characterisation tool for the EDZ. The project was divided into two parts: Work Package (WP1), which managed the control of the excavation; and Work Package 2 (WP2), which concentrated on the geophysical tests. Long term safety issues were not included into EDZ09 Project. The project work was undertaken in a specific EDZ niche (Tutkimustila 3, ONK-TKU- 3620) with Work Package 1 being concerned with the research niche excavation and Work Package 2 with activities conducted in the niche. In Work Package 2 (WP2), a series of investigations under controlled conditions for EDZ assessment was conducted before and after the excavation. These measurements were performed in drillholes and on the tunnel surface. The investigations carried out before excavation of the EDZ-tunnel define the undisturbed, baseline conditions in the surrounding rock (behind the planned tunnel wall); and the investigations carried out after excavation of EDZ-tunnel define the conditions when the EDZ already exists. The induced change in the conditions before and after excavation indicate the EDZ. The results of measurements from tunnel surfaces and from drillholes were reviewed with petrophysical sample data taken and analysed from the same location. Baseline investigations included: (1) a reflection seismic single-hole survey in a drillhole parallel to the planned tunnel outside the tunnel contour; (2) seismic tomography between two drillholes drilled parallel to the tunnel; (3) seismic tomography between two pairs of drillholes inclined forward from the tunnel in a horizontal plane at the tunnel wall level and in a vertical plane from the tunnel floor. The surveys in these holes also included geological core logging, geophysical logging, acoustic and optical drillhole imaging, differential flow logging, borehole radar measurements, and water loss measurements. Additionally, differential flow logging, water loss measurements and interference tests were conducted in three parallel drillholes inclined forward from the tunnel at tunnel floor level. Repeated investigations performed after the tunnel excavation included: (1) a reflection seismic single-hole survey carried out in the remaining drillhole parallel to the tunnel; (2) seismic tomography between the tunnel wall and the remaining drillhole parallel to the tunnel; (3) seismic tomography between the horizontally located drillholes in the wall, and between sub-vertically located drillholes in the floor; (4) borehole radar reflection in the remaining drillhole parallel to the tunnel; (5) optical and acoustic imaging in drillholes in the horizontal plane in the wall and in a sub-vertical plane in the floor; and (6) differential flow logging and water loss measurements in the holes in the sub-vertical plane in the floor and in the parallel sub-vertical holes in the floor