Assessment of geotechnical studies at the settlement of structures with emphasis on the geomorphology of Mashhad metropolis

The present research studies the impact and importance of recognizing urban geomorphology on the occurrence of settlement hazards and landslide of excavation walls in engineering structures in Mashhad metropolis. The data includes geotechnical parameters and groundwater level, and the points of settling and falling. The tools used include the urban maps of 1: 25,000 and 1: 2000 and topography of Mashhad and satellite imagery (MMS) and (TM) and (ETM) related to 1353, 1359 and 1390, and aerial photos of 1342 that using the GIS, SPSS, Excel and Matlab softwares were used for linear regression modeling and artificial neural network and the zoning hazard map was extracted at five levels. The maps show that the central part of the city, which is geomorphologically similar to the alluvial plain, and the southwest part of the city, that geomorphologically landforms of pediment and alluvial fan and mountain and fault are extremely complex in each other, have The highest probability of occurrence of the risk and the north west and west section is suitable for very low risk physical development.
The risk of the settlement buildings caused by the ground settlement in the foundation of the building, as well as the loss of soil during excavation, is one of the important issues in urban studies as well as geotechnics. Every year, we see such incidents in urban reports, and as a result, human behavior is one of the most important causes of these incidents. Although human behavior is not affected by such events, the study of scientific causes to prevent reoccurrence of this risk is very important. The metropolis of Mashhad is also witnessing a number of hazards every year, such as the fall of the excavation walls or the settlement in the foundation of the building. According to the fire department, between 1390 and 1392, seven construction workers and drivers, and five others, two of whom were pilgrims of Mashhad, have been victimized (according to the description of the fire department of Mashhad Holy). The need to address this risk is important for both human and natural reasons: First, the role of the pilgrimage and medical and tourism polygon of Mashhad, and the second type of soil and geomorphologic status of the city. The purpose of this writing is to express the importance of geomorphologic studies in urban structures and to present the zoning of risk of collapse and falling within the scope of studies with statistical modeling. Model outcomes and studies show how morphology study can be important in reducing such hazards. The hypothesis of the research is that there is a significant relationship between geomorphologic studies and the reduction of the risk of collapse and settlement, and by identifying the places prone to this risk, this risk can be largely prevented.
Study area: Considering the relevance of the risk of settlement and the collapse with building structures and the physical development of the city, the bounaries of the city's privacy were selected as a study area in 1391 in Mashhad to determine the zoning of danger of settlement and the fall in this area as a range of future development physical of the city. The area is 1080.6square kilometers and its environment is 11,501.9 km. It includes the Mashhad metropolis and part of the mountainous lands and the fans of the south and southwest of Mashhad. The studied area is geomorphologically composed of four units including mountain, plain, fans and alluvial plain. The Mashhad metropolis is located inside an alluvial basin, which covers the area from the west and southwest of the Binalud igneous massif and from the north and northeast of the Kope Dagh and hezar madjed highlands. Geomorphologic units of the study area include alluvial plain, southern and southwest fans and plains and mountains. The Kashfrood River extends along the western-eastern axis north of the study area. The Kashfrood fault along the Kashfrood River and the south fault of Mashhad along the northern slopes of Binalud has created the Morphotechnics hole in Mashhad, which Mashhad city has found in this unit of physical development.
In the study of geomorphology of this study, the urban maps of 1: 25000 and 1: 2000 and topography of Mashhad and satellite imagery (MMS) and (TM) and (ETM) related to 1353, 1359 and 1390 and aerial photos of 1342 were used. Geotechnical maps were extracted using speculation devise in 19 locations in Mashhad city. Other boreholes, which amount to almost 1500 specimens, are related to geotechnical reports of Jahd Azma Consulting Engineers. Underground water level data and psychological limit and soil dough index in ARC MAP environment were interpolated and classified using the IDW instruction. The settlement point layer first performed field identification and then was performed with a GPS device. Data were processed in Excel, SPSS, and Matlab softwares and in GIS softwares, multivariate linear regression modeling and artificial neural network were performed.
Result and The study area in this study emphasizes the geomorphology of the area including landforms such as river-beds, and fans and alluvial plains and mountainous regions. The study of soil and behavior of soil-forming materials in relation to the variables affecting it in order to prevent the occurrence of hazardous sedimentation and disintegration seems to be necessary. Studies done in this study confirm that the soil and its behavior, due to the shape of a landform that is fan or mountain, is somewhat determinating the extent of the risk of settlement and falling. In the risk zoning, it is observed that alluvial plains are the most hazardous according to the soil, but areas with no specific geomorphological complications, such as the western and eastern parts of the city, are very low in hazard zoning. In the southwestern part of the study, where several geomorphologic features are located in the opposite direction and covered in different parts, the development of constructional structures has been encountered in 40 cases and has fallen to 32% of the sessions. These landforms and complications include the part where the fault crossed the ridge of the flying flank and is separated from the plain by a relatively high slope of the mountainous area.
Studies done in this study confirm that the soil and its behavior, due to the shape of a landform that is fan or mountain, is somewhat determinating the extent of the risk of settlement and falling. In the zoning of the Alluvial plain, the highest risk of occurrence is due to its soil, but areas without any special geomorphological complications, such as the western and eastern parts of the city, are very low in hazard zoning. In the southwestern part of the study, with number of geomorphologic complications, the development of constructional structures has been reduced to 40 cases, and 32% of the sessions have been allocated. In the meantime, the variables of groundwater level and surface water flows are factors that influence the behavior of soils, and the most conspicuous point is that the type of each landform is somewhat determinative for flow and water in the studied area. For example, mountainous landforms due to high altitudes have a high psychological limit and a high sulfur index, or alluvial plain is due to its very low posture and gradient, and sometimes the very slow movement of subsurface flows, which can determine the behavior of soils and then the occurrence of the settlement and the fall, will be very influential.