Most of Iraqi soil is classified as Quaternary deposits, especially in the Mesopotamian plain and tributaries of the River Tigris. Soil varies from north to south of Iraq. These differences in soil affected the proces...Most of Iraqi soil is classified as Quaternary deposits, especially in the Mesopotamian plain and tributaries of the River Tigris. Soil varies from north to south of Iraq. These differences in soil affected the process to select the suitable type of foundation. This research is to study the effect of bearing capacity on shallow foundations in different regions of Iraq. Seventy nine samples were collected from 23 boreholes at three different locations (Mosul at the North, Baghdad at the middle and Basrah at the south of Iraq). The samples were collected at varying depth between 1 to 24 m. They were subjected to the following testes: Atterberg limits, sieve and hydrometers, consolidation, direct shear, unconfined compression and the filed (SPT test). The values of the bearing capacity parameters ( and c) were obtained from the above tests. The results obtained were used in the application of the general equation of the bearing capacity. Then, the model of a building was designed (two floors, with mat foundation type) using STAAD Pro software. The average values of bearing capacity in each region were applied in the program (Mosul = 177 KPa, Baghdad = 125 KPa and Basrah = 84 KPa). In addition, the worst bearing capacity values were also used for the three regions (Mosul = 77 KPa, Baghdad = 68 KPa and Basrah = 24 KPa). The results obtained from the average and worst bearing capacity indicated that for Mosul, we could use shallow foundation (spread and mat used if there was basement) for different areas and for buildings with many stories. For Baghdad region, shallow foundation was more suitable for building not higher than five stories. Finally, for Basrah region, shallow foundations were an appropriate selection, but for most areas deep foundation was the right choice.展开更多
A pile foundation is commonly adopted in geotechnical engineering to support structures, and its application has been extended to cold-regions engineering. In past decades, a host of scholars investigated pile behavio...A pile foundation is commonly adopted in geotechnical engineering to support structures, and its application has been extended to cold-regions engineering. In past decades, a host of scholars investigated pile behaviors and proposed design guidelines for seasonally frozen ground or permafrost. This paper reviews the research with respect to pile performance and engineering practice in cold regions, organized as follows:(1) creep tests and bearing capacity,(2) frost-jacking hazards,(3) laterally loaded piles,(4) dynamic responses,(5) refreezing due to concrete-hydration heat, and(6) improved countermeasures and design methods. We first summarize previous research and recent progress; then, predict the development trend of pile foundations in cold regions and recommend further research.展开更多
The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the bo...The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the box foundation structure as well as the instability induced failure modes to its dimensions and external loads are discussed through static model tests and wave tests. The mechanical properties of the stability of the box foundation are similar to those of embedded rigid foundations, i.e. the vertical stresses at the bottom of the box are distributed in a linear pattern under the action of vertical loads, and passive and active soil pressures are developed at the front and back sides of the box under the action of horizontal loads; there are two instability induced failure modes of the foundation structure-horizontal slide along the box base and tilting due to insufficient local vertical bearing capacity of the soil beneath the box base. The stability of box foundations can be analyzed by use of the methods applied to analysis of the embedded rigid foundations. To increase the width of the box is the most effective way to improve the stability of box foundations.展开更多
To optimize the distance between the bells in pile design,this paper reports a series of small scale tests on the uplift capacity of double belled piles embedded in dry dense sand considering different bell space rati...To optimize the distance between the bells in pile design,this paper reports a series of small scale tests on the uplift capacity of double belled piles embedded in dry dense sand considering different bell space ratios.Finite element modelling is also performed to evaluate the range of soil failure around the piles during pile uplift displacement.Test results show that when bell space ratio is 6 or 8,the uplift capacity reaches the peak value.The upper bell bears more load than the lower one for the piles with bell space ratio less than 6,while the lower bell bears more load than the upper one for the piles with bell space ratio larger than 8.展开更多
The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile unde...The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile under the same loading conditions.With the increase in horizontal loading speed,the ultimate horizontal bearing capacity of the two piles also increases,and the difference decreases gradually.Moreover,the influence of vertical loading on the horizontal bearing capacity of screw pile and monopile is studied at the horizontal loading speed of 2 mm s-1.The findings indicate that vertical load evidently affects the horizontal bearing capacity of common piles,but slightly influences the horizontal bearing capacity of screw piles.展开更多
文摘Most of Iraqi soil is classified as Quaternary deposits, especially in the Mesopotamian plain and tributaries of the River Tigris. Soil varies from north to south of Iraq. These differences in soil affected the process to select the suitable type of foundation. This research is to study the effect of bearing capacity on shallow foundations in different regions of Iraq. Seventy nine samples were collected from 23 boreholes at three different locations (Mosul at the North, Baghdad at the middle and Basrah at the south of Iraq). The samples were collected at varying depth between 1 to 24 m. They were subjected to the following testes: Atterberg limits, sieve and hydrometers, consolidation, direct shear, unconfined compression and the filed (SPT test). The values of the bearing capacity parameters ( and c) were obtained from the above tests. The results obtained were used in the application of the general equation of the bearing capacity. Then, the model of a building was designed (two floors, with mat foundation type) using STAAD Pro software. The average values of bearing capacity in each region were applied in the program (Mosul = 177 KPa, Baghdad = 125 KPa and Basrah = 84 KPa). In addition, the worst bearing capacity values were also used for the three regions (Mosul = 77 KPa, Baghdad = 68 KPa and Basrah = 24 KPa). The results obtained from the average and worst bearing capacity indicated that for Mosul, we could use shallow foundation (spread and mat used if there was basement) for different areas and for buildings with many stories. For Baghdad region, shallow foundation was more suitable for building not higher than five stories. Finally, for Basrah region, shallow foundations were an appropriate selection, but for most areas deep foundation was the right choice.
基金supported by the National Natural Science Foundation of China(Grant Nos.41731281and 41771073)
文摘A pile foundation is commonly adopted in geotechnical engineering to support structures, and its application has been extended to cold-regions engineering. In past decades, a host of scholars investigated pile behaviors and proposed design guidelines for seasonally frozen ground or permafrost. This paper reviews the research with respect to pile performance and engineering practice in cold regions, organized as follows:(1) creep tests and bearing capacity,(2) frost-jacking hazards,(3) laterally loaded piles,(4) dynamic responses,(5) refreezing due to concrete-hydration heat, and(6) improved countermeasures and design methods. We first summarize previous research and recent progress; then, predict the development trend of pile foundations in cold regions and recommend further research.
文摘The breakwater with top sealed, shallow and wide penetrating box foundations is a new type of structure, applicable to deep water and soft seabed. The relations of horizontal and vertical bearing capacities of the box foundation structure as well as the instability induced failure modes to its dimensions and external loads are discussed through static model tests and wave tests. The mechanical properties of the stability of the box foundation are similar to those of embedded rigid foundations, i.e. the vertical stresses at the bottom of the box are distributed in a linear pattern under the action of vertical loads, and passive and active soil pressures are developed at the front and back sides of the box under the action of horizontal loads; there are two instability induced failure modes of the foundation structure-horizontal slide along the box base and tilting due to insufficient local vertical bearing capacity of the soil beneath the box base. The stability of box foundations can be analyzed by use of the methods applied to analysis of the embedded rigid foundations. To increase the width of the box is the most effective way to improve the stability of box foundations.
基金Project(51778346) supported by the National Natural Science Foundation of ChinaProject(2019GSF111007) supported by the Key Research and Development Project of Shandong Province of China+1 种基金Project(ZR201808040034) supported by the Natural Science Foundation of Shandong Province of ChinaProject(2015RCJJ010) supported by the Talent Introduction Research Start-up Fund Project of Shandong University of Science and Technology,China。
文摘To optimize the distance between the bells in pile design,this paper reports a series of small scale tests on the uplift capacity of double belled piles embedded in dry dense sand considering different bell space ratios.Finite element modelling is also performed to evaluate the range of soil failure around the piles during pile uplift displacement.Test results show that when bell space ratio is 6 or 8,the uplift capacity reaches the peak value.The upper bell bears more load than the lower one for the piles with bell space ratio less than 6,while the lower bell bears more load than the upper one for the piles with bell space ratio larger than 8.
基金funded by the National Natural Science Foundation of China(No.51779171)。
文摘The horizontal bearing capacity of the screw pile and monopile was analyzed by model tests.Results showed that the horizontal bearing capacity of the screw pile was significantly greater than that of the monopile under the same loading conditions.With the increase in horizontal loading speed,the ultimate horizontal bearing capacity of the two piles also increases,and the difference decreases gradually.Moreover,the influence of vertical loading on the horizontal bearing capacity of screw pile and monopile is studied at the horizontal loading speed of 2 mm s-1.The findings indicate that vertical load evidently affects the horizontal bearing capacity of common piles,but slightly influences the horizontal bearing capacity of screw piles.
