Taking our geotechnical knowledge to listeners around the world: three summertime appointments for Italian Geotechnics.
Our Technical Director, Vittorio Manassero, will be attending and speaking at the XXVI Convegno Nazionale di Geotecnica (26th Italian Geotechnical National Congress) in Rome from 20th through 22nd June, at the training course on "Directional Drilling and Microtunnelling in Special Geo-engineering Works" at Turin Polytechnic from 29th through 30th June and at the 5th International Grouting Conference (Grouting 2017) in Honolulu, Hawaii, from 10th through 12th July.
At the Italian Geotechnical National Congress (on the afternoon of Tuesday 20th, in the San Francesco room, as part of the 1B session), Mr. Manassero will be giving a presentation entitled "Crossing under monumental buildings by TBM, through a soil improved by grouting" (co-author Giuseppe Di Salvo). The lecture deals with a soil improvement operation by grouting, carried out through tubes à manchettes of extraordinary length, installed inside HDD boreholes. As part of the Warsaw Subway Line No. 2 project, two TBM tunnels were required to cross under historical buildings in the "Praha" district. In order to mitigate the risk of settlements, a preliminary soil improvement was designed. Due to the particular layout of the buildings, an extreme solution was conceived and applied. Starting from the surface, boreholes from 210 to 260 m long, with curved paths, were drilled by HDD technology. Each tunnel was fitted with 24 grouting pipes around the outside of the tunnel to be bored. Grouting was performed by selective and repeated procedure, injecting first a high penetrability cement-based grout and then a silicate-based chemical mixture.
At the training course on Directional Drilling (on Thursday 29th in the Bibolini room at Turin Polytechnic), Mr. Manassero will be giving a presentation entitled "Applications of directional drilling to landslide stabilization: micro-drains of unconventional length and base discharge of draining wells". Directional Drilling technology has recently spread to special geo-engineering works such as soil and rock improvement by grouting, jet grouting and artificial ground freezing. This technology is based on the principle that the actual position and path of the drilling tool may be measured and known in real time and the direction corrected by special tools and drilling bits. In such a way it is possible to steer boreholes, thus avoiding excessive deviations from the design theoretical path but also enabling us to follow predetermined curved paths if necessary.
During the 5th International Grouting Conference, Mr. Manassero will be giving two presentations. The first one (on Wednesday 12th 3.00:4.30 P.M., as part of the 1A20 / Jet Grouting - Verification and Testing session) is entitled "An unconventional application of jet grouting to install 4900 kN ground anchors in loose alluvial soil". This lecture deals with a particular application of jet grouting, where the improved soil columns acted as the bonding section of unusually high capacity ground anchors installed in loose alluvial soil. A retaining wall, 25 m high, constructed to support refuse and waste material, after its construction began to suffer displacements that became so large as to reach very critical conditions in terms of stability safety. To improve its stability, 120 ground anchors capable of withstanding a 4900 kN working load each were installed. The bonding section was achieved by a 1.2m dia. jet grouting column. The second presentation (on Wednesday 12th 1.00:2.30 P.M., as part of the 2A20 / Construction and Innovation session) is entitled "Soil improvement thanks to an extra-long application of directional drilling" (co-author Giuseppe Di Salvo). This lecture deals with the same case study presented at Italian level to the XXVI CNG, here presented at the International level.