جستجوی مقالات مرتبط با کلیدواژه "ترکیدگی لوله" در نشریات گروه "عمران"

In general, any damage or breakage in a building's foundation will cause it to settlement, resulting in damage to both the foundation and the structure itself. Considering the extent of the construction, it is important to pay attention to the issues related to the design and performance of the foundation of the structure. From a geotechnical engineering perspective, expansive soils are among the most important soil groups that need to have their characteristics accurately determined before design studies. Such soils cause significant damage to structures. For this reason, the behavior of expansive soils should be investigated and determined in advance to minimize the damage caused to the structure. Shallow foundations such as singular and strip foundations may be affected by non-uniform settlement, rotation, and bending moment due to soil expansion, leading to damage. One of the factors leading to non-uniform settlement and rotation in foundations is water infiltration under the foundation. Often, soil layers near the ground surface, crucial for engineering purposes, are in an unsaturated state. Thus, understanding the precise behavior of soil necessitates the application of complex unsaturated soil mechanics principles. In expansive soils, water infiltration causes a reduction in matric suction and consequently a decrease in shear strength and an increase in soil volume. In this paper, a numerical investigation of the behavior of shallow foundations in two models of singular and strip foundations under changing factors such as pipe bursting and absorption well has been conducted. Using Geostudio SIGMA/W software and Couple analysis, the simultaneous effect of change in matric suction and change in stress and strain has been investigated. Additionally, the effect of the number of building stories and changes in the position of pipe bursting or absorption well on the results has been studied. The analysis of the results indicates that pipe bursting and absorption wells lead to an increase in pore water pressure in the soil over time. Additionally, due to the characteristics of expansive soil, The damage to the structure increases with the passage of time and it has grown more in the first month. Also, the category of damage to the structure is more severe for the models where the one-story structure is built on the foundation. Due to the bursting of the pipe or the existence of the absorption well and also the expansive property of the soil under the foundation, the lower the intensity of the load on the soil or the number of floors of the building, the higher the swelling values of the soil will be. So it is recommended to construction tall structures on this soil. The amount of damage in the case of pipe burst is estimated to be higher than that of the absorption well. In terms of angular distortion, water permeation under the foundation and in neighboring borders, and in terms of horizontal strain, permeation under the center of the foundation are responsible for the most damage. Overall, the damage rating to the structure is higher for singular foundations than for strip foundations, and in many cases, the structure will experience severe damage, thus the use of strip foundations with appropriate thickness for buildings located on expansive soils is recommended.

Due to the increase in population and the increasing need for construction, the issues related to excavation and stability of the excavation have been given importance. The stability of excavations can be controlled and improved by various methods such as anchoring, retaining walls, shielding, etc. that in each project, according to the characteristics of that project and the type of factors threatening the stability of that excavation, one or more stabilization methods can be used. The excavation investigated in this research is stabilized by two pile-anchor and concrete pile methods. One of the factors leading to the instability of the excavation is the infiltration of water into the excavation. Water infiltration into the excavation can be due to various reasons such as rainfall, rise of the underground water level, pipe burst, etc.; Therefore, the possibility of water infiltration into the excavation should be checked in each excavation, and necessary measures should be taken in case of water infiltration. matric suction is defined as the difference between pore air pressure and pore water pressure, which plays a major role in the shear resistance behavior of unsaturated soils; Now, water infiltration reduces matric suction and as a result reduces shear resistance and increases soil volume in expansive soils. The excavation studied in this research has been exposed to factors that change matric suction such as pipe burst, absorption well and climate conditions. The boundary conditions of pipe bursting and absorption well are assumed for a period of one year; Also, the weather conditions have been obtained from the meteorological data of the two rainy months of Sarakhs city. Using sigma/W software and Couple analysis, the simultaneous effect of change in matric suction and change in stress and strain has been investigated. Also, the Penman-Monteith method has been used for the calculation of evaporation and transpiration to model the climate conditions. In this research, a comparison was made between different excavation stabilization situations (pile-anchor and pile method) under different conditions of matric suction (pipe burst, absorption well and weather conditions). Also, in this research, the effect of the location of the burst pipe and absorption well (distance from the excavation wall) on factors such as deformations, the moment created in the pile and the forces created in the anchors (behavior of the excavation) was investigated. Considering the destructive behavior of expansive soils in unsaturated conditions, the soil studied in this research is of expansive type. The characteristics of the modeled soil are related to the area of Sarakhs city. In order to consider the effect of soil swelling, the used elasticity modulus is related to the effective stress and as a result matric suction, which is called the swelling modulus. The results showed that the increase in moisture in the soil and as a result the decrease in matric suction in the swelling soil increases the force in the anchors and the bending moment in the pile. Also, the increase in the force of the anchors and the displacement created in the case of pipe bursting and absorption well modeling is much more than the conditions of the climate boundary effect for the two rainy months of the year. By increasing the distance of the absorption well and the bursting of the pipe from the excavation, the increase in the force created in the anchors decreases. climate conditions affect the upper 6 meters of the excavation, i.e. the active zone.