Bearing capacity of peat treated with deep mixing cement columns

Dehghanbanadaki, Ali

Bearing capacity of peat treated with deep mixing cement columns

dc.contributor.author	Dehghanbanadaki, Ali
dc.date.accessioned	2024-07-23T01:35:35Z
dc.date.available	2024-07-23T01:35:35Z
dc.date.issued	2014
dc.description	Thesis (PhD. (Civil Engineering))
dc.description.abstract	Peat is highly acidic soil well known for its low bearing capacity and high compressibility. Due to the poor engineering properties, construction on peat deposits without improvement is very difficult. The aim of this study is to evaluate the feasibility of the deep cement mixing (DCM) method to increase the shear strength of peat soils. Thus, 13 physical modeling tests on peat, stabilized by a group of DCM columns were conducted to determine the ultimate bearing capacity and failure patterns of the improved ground. In this research three length / depth ratios of 0.25, 0.5 and 0.75 and three area improvement ratios (a) of 13%, 20% and 26% were selected. A rigid rectangular steel footing was used to load the treated ground with an increment of vertical stress of 1 kPa. The mixed design of DCM columns to be installed in the peat was determined based on strength tests on several mixtures consisting of peat with different dosages of cement and natural fillers. Finally, numerical modeling was performed to simulate and compare the effect of the DCM columns on the ultimate bearing capacity of peat soil using Plaxis 3-D foundation software. The results of the unconfined compressive strength tests on the shear strength of the DCM columns indicated that binder dosage of 300 kg/m ' cement could increase the bearing capacity of stabilized peat up to 850% compared to untreated peat. In the physical modeling tests, ultimate bearing capacity of peat stabilized with end-bearing and floating DCM columns increased using higher a and higher length / depth ratio. The ultimate bearing capacity of peat treated with endbearing DCM columns using area improvement ratio of 26% increased up to 240%, while in the case of peat stabilized with floating DCM columns, the average increase of the ultimate bearing capacity was 60% compared to the untreated peat. Punching shear failure patterns were observed in untreated peat and peat treated with floating DCM columns. On the other hand, progressive cracks and small heave was observed around the footing in the case of peat treated by end-bearing DCM columns. Finally, it could be concluded that, both floating and end-bearing DCM columns increased the ultimate bearing capacity of untreated peat, while the effects of end-bearing DCM columns on the ultimate bearing capacity were more dominant than floating columns
dc.description.sponsorship	Faculty of Civil Engineering
dc.identifier.uri	http://openscience.utm.my/handle/123456789/1274
dc.language.iso	en
dc.publisher	Universiti Teknologi Malaysia
dc.subject	Peat soils
dc.subject	Mixing—Engineering
dc.subject	Bearing capacity
dc.title	Bearing capacity of peat treated with deep mixing cement columns
dc.type	Thesis
dc.type	Dataset