After the incident, the Yunnan Provincial Department of Land and Resources and the Department of Transportation sent an expert group to investigate, and the expert group agreed that it was indeed a "natural disaster caused by heavy rainfall." However, there are some problems in the construction of the new No.3 highway, such as building without approval, rushing for the construction period, and commissioning before completion and acceptance.
From K25+450 to K26+480 of Xinsan Expressway, there are three diseases, including two collapses and pavement cracks 1. The road where the accident happened is located halfway up the mountain. Four lanes in both directions have collapsed, and a lot of stones, mud and concrete have been washed into the river valley by the roadside. The car that fell into the valley was badly damaged.
Where the highway collapses, the subgrade is soft and there is obvious subsidence when stepping on it. The destroyed retaining wall is mainly masonry, and the reinforced concrete retaining wall is relatively complete. The mortar protective layer of highway slope cracked in many places, the biggest crack was as long as twenty or thirty centimeters, and the steel wire mesh was all exposed. The expressway was opened to traffic illegally before the completion acceptance, and the opening ceremony is planned to be held on June 30, 20 1 1. Later, the ceremony was cancelled unexpectedly.
According to the construction personnel, the geological environment along Xinsan Highway is complex, the construction period is short and the task is heavy, and the project is under great pressure from the beginning. In the later period of highway construction, Xinping County shouted the slogan of "Do it in 60 days", and the progress of the project was reversed, and the workers all worked overtime in the later period.
It is understood that there are more important reasons besides meeting the travel requirements of the masses.
Yunnan Provincial Department of Land and Resources and Department of Transportation sent experts to the site for investigation. The expert group believes that the steep terrain, poor engineering geological conditions, and the collapse caused by the increase of hydrostatic pressure due to heavy rainfall are natural disasters induced by heavy rainfall. An expert from Yunnan Provincial Department of Transportation who participated in the survey said that subgrade treatment, retaining wall strength and asphalt thickness all met the requirements. According to the local geological conditions, two sets of restoration schemes were designed. First, it costs 6.9 million yuan to build an anti-slide retaining wall, but it depends on whether the pile foundation is damaged. If the pile foundation is damaged, the cost will increase. This plan will take about three months. The second option is to bridge the bridge, with a capital of about 7.6 million yuan and a time of at least half a year. Repairing the bridge can avoid the landslide area and reduce the potential safety hazard.