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Why did Baoji Chengdu Railway collapse? Specific situation of Baoji Chengdu Railway collapse rescue

At 10:00 p.m. on July 12, the village began to fall asleep. With a loud bang, nanjiashan mountain across the river collapsed and Baocheng railway was buried. Why did Baocheng railway collapse? Specific situation of collapse rescue of Baoji Chengdu Railway

specific situation of collapse rescue of Baoji Chengdu Railway

At 10:00 p.m. on July 12, the village fell asleep, with a loud "bang!" and "over! The railway collapsed!" old Qu, a villager, bounced up from his bed & hellip; & hellip;

Affected by continuous heavy rainfall, from July 12 to 7:00 a.m. on July 13, there was a continuous mountain collapse disaster between wangjiatuo and lesu river of Baocheng railway, with the collapse volume of about 75000 square meters. BAIQUESI tunnel entrance was buried, among which the upper line collapse buried more than 100 meters, more than 20 meters high and 6 meters wide, with no casualties.

According to the Meteorological Bureau of Lueyang County, Hanzhong City, as of July 16, the total rainfall in the region has exceeded 826 mm, the largest rainfall in 50 years. It can be seen from the rescue site of Baoji Chengdu Railway that the progress of clearing up the landslides has been advancing and retreating repeatedly. Due to the continuous rainfall, there are new landslides on the mountain slope.

Collapse refers to the natural phenomenon that the road, mountain, building or mine collapses and falls under the condition of non-human natural force. The specific performance is that the steep slope beside the road and dam is affected by weathering, water immersion and vibration, or the top of the tunnel, tunnel and mine collapses suddenly due to the soft soil rock stratum. The types of landslides are mainly rainwater landslides, earthquake landslides, construction landslides, etc. In fact, there are also signs of landslides. When there is a large amount of muddy water at the bottom or drain hole of the slope, it shows that the water in the slope has been saturated, there are cracks or newly formed steps at the middle or top of the slope, exposing fresh soil, which are all signs of landslides. When these signs are found, they should be away from the slope as soon as possible.

According to China Railway Xi'an Bureau Group Co., Ltd., the rescue work for the collapse of the mountain between wangjiatuo and lesu river of Baocheng railway is still in intense progress. Since the occurrence of water disaster, there have been heavy rainfall on the site for many times, and the geological condition of the collapsed slope has been constantly changing. The slope fracture zone appears in the collapsed section, which seriously affects the rescue work.

The rescue work of the mountain collapse between wangjiatuo and lesu river of Baoji Chengdu Railway is still in intense progress. Since the occurrence of water disaster, there have been heavy rainfall on the site for many times, and the geological condition of the collapsed slope has been changing constantly, which seriously affects the rescue work.

Longjunqi, a member of Hanzhong Public Works section who participated in on-site rescue, said: 'the biggest difficulty in clearing the collapse at the site is heavy rainfall. Frequent heavy rainfall causes repeated collapse and rockfall of the mountain slope. In addition, the geological conditions at the site are extremely poor, resulting in new collapse surface repeatedly. The terrain conditions on the mountain are constantly changing and quite complex, so there is no way for personnel and machinery to work under the collapse slope for a long time'.

Xi'an Bureau Group Co., Ltd. invited geological experts to jointly inspect the slope condition of the collapsed mountain, believing that the slope is still creeping and deformation, and the slope collapse may be further expanded. In order to ensure the safety during the line rescue and the driving safety after the line is opened, Xi'an Bureau Group Company decided to implement load reduction for all the mountain slopes within the influence range of the collapsed slope fault zone. At present, the site is organizing personnel to further inspect and monitor the mountain, and to study the load reduction scheme with geological experts. On site rescue personnel are also trying their best to build the climbing passage of excavators and other equipment, so as to prepare for the load reduction work as soon as possible. In addition, affected by the flood, on July 17, the xi'an-chengdu high-speed railway reconnected eight bullet trains, increasing the transportation capacity to Sichuan and shutting down 11 ordinary trains. Yesterday, 11 ordinary trains running through Baocheng railway were shut down, and today, 18 will be shut down. In order to increase the transportation capacity in and out of Sichuan, xi'an-chengdu high-speed railway has reconnected 8 bullet trains yesterday, and will continue to reconnect 8 bullet trains today to relieve the passenger pressure.

The main reasons for the collapse are as follows: 1. The slope is too steep, which makes the soil stability not enough, and causes the collapse phenomenon. 2. Rainwater and groundwater infiltrate into the foundation pit, making the soil soft, increasing the weight and reducing the shear resistance, which is the main reason for the collapse. 3. A large number of soil or parking machines and materials near the upper edge of the foundation pit, or due to the action of dynamic load, the shear force in the soil exceeds the shear strength of the soil. 4. The earth excavation sequence and method follow the principle of "from top to bottom, excavation in layers; slotting support, first support and then excavation".