Tunnel construction below or adjacent to piles will affect the performance and eventually the stability of piles due to ground deformation resulting in the movement of piles and changes in the axial force distribution along the piles. A three dimensional finite element analysis using PLAXIS 3D (2013) was performed to study the behaviour of a single pile and 3 x 3 piles group during the advancement of shield tunnelling in ground. The 10-node tetrahedral elements were used to model both the soil and the tunnel lining. The Hardening Soil (HS) model was used to simulate the soil structure interaction at the tunnel-soil interface. An isotropic elastic model was used for the pile, piles cap, tunnel lining and tunnel boring machine shield (TBM). Several parametric studies were attempted including the longitudinal, lateral, and vertical tunnel location relative to pile embedded in different types of soil (clay or sand). The results showed that the pile head settlement increases during the tunnelling advancement in larger values than that for ground surface settlement. A zone of influence was determined in the range of twice the tunnel diameter in the longitudinal direction (forward and backward of the pile), and transverse direction (left and right of the tunnel centreline). If the tunnel boring is kept off this zone then there is no fear of pile collapse.

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This research is concerned with the use of petroleum residues to stabilize Baiji sand dunes. The purpose of this research is to study the stabilizing effect of these residues irrespective of their possible toxicity to plant and environment. Two petroleum mixtures were prepared in different mulching rates to test their efficiency in stabilizing sand dunes. Those mixtures were added to the dune samples with variable mulching rates, mixtures temperatures and initial water contents. Mechanical stability was estimated from percent of dry aggregates greater than 0.84 mm and percent of aggregates less than 0.42 mm. The mixtures of petroleum residues used in this study were found to be effective in forming large amounts of nonerodible aggregates greater than 0.84 mm and reducing the erodible aggregates less than 0.42 mm. treated samples also showed a good stability against breakdown under repeated sieving and the effect of cyclic freezing and thawing on the mean weight diameter factor MWD. The results of repeated sieving test RST showed that petroleum mixtures create a stable crust preventing the bare sand dunes from erosion.

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The purposes of this study are to investigate and evaluate the benefits of using of geogrids as a circular pipe of two different lengths of (20 cm and40 cm) under the footing base in improvement of bearing capacity and settlement in term of the bearing capacity ratio (BCR) and the settlement reduction factor (SRF). A load-frame assembly was designed for the experimental work. Two types of aluminum rigid foundation were used; flat footing and shell footing of dimensions (20 20 cm) and different angles of (20˚, 30˚, and 45˚) for shell. Sand rainer device technique was used to fill the tank to obtain a homogenous sandy soil. The result show that using a circular geogrid with a length (H=20cm) leads to increase the BCR by (14-41)% higher than that for unreinforced sand, while increasing the geogrid length to 40 cm leads to increase BCR by (6-19)% .The SRF for a certain footing decreases with decreasing the geogrid length from 40 cm to 20 cm by (11-21) % .This may be related to the punching effect caused by the longer geogrid through the loose sand stratum.