Technological methods of pile walls construction for stabilisation of landslides

Magistrska naloga se osredotoča na področje geomehanike. Glavna tema naloge je predstavitev tehnoloških postopkov pri uporabi pilotnih sten za stabilizacijo plazov. V prvem delu naloge so predstavljene splošne teoretične osnove o plazovih. Podrobneje so opisani dolgotrajni in kratkotrajni dejavniki ter notranje in zunanje sile, ki so največkrat vzrok za nastajanje plazov. V tem delu so klasificirani posamezni tipi plazov, glede na njihove lastnosti. Ti se največkrat delijo glede na vrsto plazenja, sestavo plazu, hitrost plazenja, globino, obliko drsne ploskve in samo stanje plazu. Za uspešno geotehnično sanacijo plazov s pomočjo pilotnih sten so potrebne predhodne raziskave, ki se izvajajo na terenu kot tudi v laboratoriju. V okviru tega so podrobneje opisane raziskave s, standardnim penetracijskim testom, dinamičnim penetracijskim preizkusom, presiometrom in inklinometrom ter raziskave s pomočjo geotehničnih vrtin. Dobljene rezultate terenskih preiskav zaradi natančnosti podkrepimo še z laboratorijskimi. V okviru tega sem v nalogi opisal enoosni in triosni tlačni preizkus ter strižni trdnostni preizkus. V drugem delu naloge sem opisal in primerjal tehnološke postopke pri vgradnji pilotnih sten za stabilizacijo plazov. V tem sklopu so podrobneje predstavljene selekcije geotehničnih tipov podpiranja nestabilnih brežin z uporabo osnovnih gradnikov pilotnih sten, kot so to piloti, naglavne grede ter sidra (aktivna in pasivna). Naloga opisuje različne načine vgradnje pilotov. Obravnavani so tehnološki postopki za pilote, vgrajene z razmikom zemljine (vtisnjeni ali zabiti piloti), pilote vgrajene v pripravljeno izvrtino (uvrtani piloti), kopane pilote (Benotto piloti) ter injicirane pilote (Jet Grouting piloti). V magistrski nalogi je največji poudarek na tehnoloških postopkih izvedbe uvrtanih pilotov (s kolono, z bentonitno izplako, CFA piloti), ker se ti najpogosteje uporabljajo kot elementi pilotnih sten za stabilizacijo plazov. Tehnične osnove so podkrepljene še z praktičnim primerom, v katerem opisujem sanacijo plazu Znosnice na regionalni cesti R1-207/1413 Col – Ajdovščina od km 2,400 do km 2,750. Pri sanaciji sem s pomočjo programske opreme SLIDE porušno brežino preveril na mejno stanje nosilnosti (MSN) in mejno stanje uporabnosti (MSU), pri čemer sem se navezoval na 2. projektantski pristop v skladu s standardom EC7. S pomočjo dobljenih rezultatov sem ugotovil, da je vgradnja obravnavane podporne konstrukcije (sidrane pilotne stene) ustrezna za stabilizacijo porušne brežine, saj so dobljeni varnostni faktorji, ki so bili opravljeni za tri različne geotehnične profile večji od tistih, ki so določeni z Eurocode standardi (FS > 1,25).The dissertation concentrates on the field of geomechanics. The subject of the study is the presentation of technological procedures in the application of the pilot walls for the stabilisation of landslides. The first part of the dissertation deals with the general theoretical introduction of landslides. There is a relatively detailed description of the long-lasting and momentary factors and of the internal and external forces. These forces are mostly to blame for the emergence of landslides. Next, a classification of the individual types of landslides are given according to their characteristics. They are classified according to the following: the type of land sliding, the structure, velocity and depth and the shape of the sliding surface, and ultimately, the condition of the landslide. In order to achieve the geotechnical reconstruction of the landslides using the pilot walls there needs to be some investigation done, both in the laboratory as well as in situ. Within the framework, the investigations were described using the following: geotechnical boreholes, the standard penetration test, the dynamic penetration test, the pressuremeter test and the inclinometer. The obtained results of the site investigations were further supported by the results in the laboratory. Within the framework there is a description given of both, the one dimensional and triaxial pressure tests, and that of the direct shear test. In the second part of this dissertation there are a description and a comparison of the procedures for the installation of the pilot walls for the stabilisation of landslides. There is a detailed presentation of the selection of geotechnical types of stabilisation of unstable slopes using the basic building blocks for pilot walls comprising pilots, patches and anchors (active and passive ones). The dissertation provides the description of various technological procedures for the installiation of the pilots. The specific technological procedures were examined for the pilots built in by soil spacing (imprinted or driven in), pilots inserted into the prepared hole (drilled-in pilots), excavated pilots (Benotto pilots) and injected pilots (Jet Grouting pilots). The main emphasis was placed on the technological procedures of implementing drilled pilots (with a column, with bentonite drilling muds, and CFA pilots) because these are the most commonly used for the stabilisation of landslides. The technical principles are underlined by the practical example in which there is a description of the landslide remedial works carried out on the regional road R1-207/1413 Col – Ajdovščina from km 2,400 to km 2,750. Destabilised slope or reconstruction slope has been interpreted in computer programme SLIDE in which i have verified state of load bearing capacity and the limit state of usability. The reconstruction of destabilised slope has been done according to the second engineering approach in accordance with the standard EC7.On the basis of the obtained results it was established that the instalment of the the anchored pilot wall meets the requirements for stabilisation of the slope since the obtained safety factors, which have been accomplished for three different geotechnical profiles, are greater than those defined by the Eurocode standards (FS > 1,25)