Study On Reinforcement Mechanism And Safety Analysis Method Of Reinforced Soil Slopes

It is of great significance to develop an effective safety evaluation methodof reinforced slopes for controlling and preventing landslide disasters, forimproving the economic economy and ensuring the safety level of reinforcementprojects. The stabilizing pile was selected as the representative reinforcementstructure in the investigation of behavior of reinforced slopes in this thesis.Serialized centrifuge model tests, on the basis of development of new testdevices, were conducted to reveal the failure mechanism and reinforcementmechanism of reinforced slopes. Accordingly, a simplified, practice-facedsafety analysis method was proposed to evaluate the stability of pile-reinforcedsoil slopes. The main results and new findings are as follows:1. A simulation system was developed to realize the piling process of pilesand surface loading on the top of a slope with high precision in flight of thecentrifuge at high g-levels. A new type of structual pile was produced with aunique shear failure mode and controllable shear strength.2. A series of centrifuge model tests of slopes reinforced with differentstructures such as stabilizing piles were conducted to reveal the responsecharacteristics and influencing factors of reinforced soil slopes under theconditions of earthquake, surface loading and self-weighted loading.3. The failure mechanism of pile-reinforced slope was obtained on the basisof observations of centrifuge model tests, including:(1) The failure ofpile-reinforced slopes were catagorized into four types failure modes accordingto the relationship between the slip surface and location of piles, namely slipsurface passing through the piles, slip surface passing by the pile, local failure,and composite failure.(2) The progressive failure process of the reinforced soilslopes was confirmed and quantitatively determined using the measurabledeformation.(3) The coupling mechanism of the process of deformationlocalization, the failure process of soil slopes, and response of stabilizing pileswas illustrated with the features of interaction as both cause and effect, alternate development, and coupling change.(4) The diverse failure modes weredependent on the deformation behavior under different loading conditions.4. The results of the centrifuge model tests of the reinforced andunreinforced slopes were compared to indicate that the piles significantlyreduced the deformation of soil slope and its influence gradually decreased tothe internal slope from the piles. The pile reinforcement mechanism wasconcluded as follows: The piles performed a significant interaction with thenearby soil and exhibited dominant compression effect; such an effect wastransferred to the internal slope away from the piles within the pile influencezone with a conversion of compression effect and shear effect; the shear effectbecame dominant near the potential slip surface and delayed the deformationlocalization so that the formation of slip surface was prevented; thus thestability level of the slope was increased.5. The aseismic reinforcement mechanism of different structures, includingthe pile, the geotextile, and the nail was yielded based on seismic centrifugemodel tests. The reinforcement mechanism, together with the analysis methods,was verified to be universal.6. A simplified Bishop slice method was proposed to analyze the stabilitylevel of pile-reinforced strain-softening slopes on the basis of an equivalentmodel used to capture the three-dimensional pile effect. The proposed methodwas confirmed by the centrifuge model tests. The method was applied to thereal-world design of pile reinforcement for a dyke slope, and the analysis resultswere used to determine a significant reinforcement zone.