Introduction
Mass movements include all movements that occur under the influence of mass weight. The landslide occurred in the last days of 2018 and early 2019 after floods in many provinces of the country, including North Khorasan, Golestan, Semnan, Mazandaran, Gilan, Hamedan, Lorestan, Kurdistan, Kermanshah, East and West Azerbaijan, and Zanjan. Due to the large number of landslides in rural areas of the country, the perspective of moving to another location and escaping from landslides has changed and the approach of stabilizing the landslides that have occurred and building in situ has been replaced. Therefore, the stabilization and stabilization of a large number of landslides that occurred in late 2018 and early 2019, including the landslides in Hossein Abad Kalpoosh village in Miami County, Semnan Province, was placed on the agenda of the responsible executive agencies.
Materials and methods
Hossein Abad Kalpoosh village is located in Kalpoosh district of Miami city in Semnan province, at coordinates 37/2003445 and 55/736813. This village is located in Sudaghlan rural district (Razvan) and according to the census of the Statistical Center of Iran in 2016, its number of households was 1013 and its population was 3514. Upstream of this village, a Kalpoosh reservoir dam has been constructed close to the village, which has been impounded in recent years. The research method in this study is based on library surveys and studies and field observations. In this regard, information related to the geological, tectonic and landslide conditions that have occurred in the village area is examined in a library manner, and then the method of landslide management and stabilization is examined. After completing the geological information, faults, landslides that have occurred, and their location, the data will be analyzed and the methods and technical measures taken to stabilize and stabilize landslides will be examined in order to prevent the displacement of the village and the migration of villagers, and to continue the settlement of villagers in the current location of the village, and to determine the direction of village development and their efficiency.
Results and discussion
A large number of landslides also occurred in the village of Hossein Abad Kalpoosh in Miami County, Semnan Province. The landslides that occurred in the village were categorized into 5 different zones, including 1- the landslide zone downstream of Kalpoosh Dam, 2- the landslide zone above the neighborhood and the southern slopes of the Ghoshe-Dagarman River, 3- the landslide zone above the Saadat Abad neighborhood, 4- the Besat Abad landslide zone, and 5- the landslide zone of Hassan Abad neighborhood and its upstream slopes. The largest landslide area is located downstream of the Kalposh Dam, which has destroyed many homes. This landslide, with an area of about one and a half hectares and an average depth of 11 square meters, occurred in the heart of a large old landslide area. This landslide, with an area of about one and a half hectares and an average depth of 11 square meters, occurred in the heart of a large old landslide zone. It seems that this old landslide in the downstream section of Kalpoosh Dam had a great depth of more than 30 meters and occurred at the border of wind-blown and weak marl deposits with strong underlying limestone bedrock, and in some places it also contains fragments of the underlying bedrock. The recent landslide occurred on March 11, 2018, with a combined rotational-transitional movement, after heavy snowfall in February and heavy rainfall in March. Although the existence of an old landslide and the heavy rainfall mentioned above played an important role in the occurrence of this landslide, the available evidence indicates that the more effective role was played by the rising water level in the Kalpoosh Dam reservoir, the seepage of water through the crushed rocks of the reservoir wall, and the saturation of the soil mass from the lower part. This is evidenced by the occurrence of numerous springs and seepages in this range, which continued for many months after the landslide occurred, and only with the lowering of the water level in the reservoir, these seepages have begun to decrease. The recent landslide occurred on March 11, 2018, with a combined rotational-transitional movement, after heavy snowfall in February and heavy rainfall in March. Although the existence of an old landslide and the heavy rainfall mentioned above played an important role in the occurrence of this landslide, the available evidence indicates that the more effective role was played by the rising water level in the Kalpoosh Dam reservoir, the seepage of water through the crushed rocks of the reservoir wall, and the saturation of the soil mass from the lower part.
This is evidenced by the occurrence of numerous springs and seeps in this range, which continued for many months after the landslide occurred, and only decreased as the water level in the reservoir decreased. The landslides damaged a large number of rural homes, facilities and infrastructure. In order to stabilize and stabilize the landslides that occurred in the village, 8 machine boreholes and 6 geoelectric profiles with a dipole-dipole array, three S and P wave boundary rupture seismic profiles, single station and microseismic array surveys (microtremor) including one in-situ array survey and 17 single station surveys have been conducted. Subsequently, stability analyses and landslide stabilization options were conducted, and finally, plans and implementation plans were presented to stabilize the village's landslides and make rural homes safe, and the aforementioned plans have been implemented.
Conclusion
By stabilizing, stabilizing, and securing the village of Hossein Abad Kalpoosh, the migration and relocation of approximately 1,000 households with a population of over 3,500 people was prevented, and the harmful consequences of unsuccessful relocations were prevented. According to available information, 881 villages have been displaced across the country by 2015, most of which were displaced due to risks arising from various natural disasters, with the most important risks causing displacement including floods, earthquakes, and landslides, so that more than 74 percent of displacements in the country are due to the above factors (Gerkani et al., 2018). Sabouri and Garkani (1403) conducted a field study of 9 new sites of relocated villages, all of which were unsuccessful in their relocation and the village was not formed in the new site. Therefore, by adopting recommendations and conducting studies and implementing sustainability plans in the village of Hossein Abad Kalpoosh, the repetition of unsuccessful and costly experiences of rural relocation has been prevented.