Thứ Ba, 23 tháng 12, 2014

Tunnel collapse due to poor construction


The Ministry of Construction on Monday urged the Government to suspend construction of the Da Dang-Da Chomo hydropower plant in Lam Dong province and investigate the cause of the tunnel's recent collapse. 



The tunnel collapsed last week, trapping 12 workers inside for 81 hours. They were rescued and taken to Lam Dong General Hospital for treatment on Friday. All workers recovered and have been discharged.
Deputy Minister of Construction Le Quang Hung said the tunnel might have been poorly constructed and unable to bear pressure from the land above it. It should be investigated to prevent more incidents from occurring, he said.
The investor and contractors should take the blame for the incident, because they didn't study the geological conditions carefully enough or design the tunnel correctly, Hung said.
However, the ministry would review construction progress to find out who is at fault, he said.
Hung said the Government would cite regulations in two decrees on the construction of hydropower plants to investigate transgressions committed during construction. Decree 209 would be used for work completed before 2013, and Decree 15 would be used from 2013 onwards.
In Decree 209, Government agencies merely issued rules to manage the construction of government building projects. They trust the investors and contractors to follow those rules.
In Decree 15, investors and contractors must submit technical reports to the Government so it can monitor their progress and the buildings' quality.
Under the second decree, the Ministry of Industry and Trade is responsible for testing designs and monitoring the construction of hydropower plants.
Tunnel collapse worsens concern over hydropower projects
Many accidents have occurred at hydropower plants in the central and Central Highlands regions with the latest one being a tunnel collapse at Da Dang-Da Chomo project which left 12 workers trapped inside have worsened concern over the quality of hydropower works together with their consequences.
Consecutive earthquakes recurred at the Song Tranh 2 hydropower plant reservoir in the central province of Quang Nam in 2012.
Scientists and experts have conducted surveys and studies and concluded that the earthquakes were induced by water accumulation at the plant’s reservoir, and that the Song Tranh 2 hydropower plant is still safe. However it has failed to set local people’s mind at rest as their properties have been damaged by the tremors.
In another uncommon case a truck collided into and collapsed a 60m long dam at Dak Mek 3 in the Central Highlands province of Kon Tum.
In the same year, a 30m dam section at Dakrong 3 hydropower plant breached in October after a medium rainfall, unleashing swift-flowing water to cause a total damage of VND20 billion (US$936,000) in the lower reaches.
Nuoc Trong hydropower plant has not been built but several cracks have been visible in the dam body since the reservoir began accumulating nearly 290 million cubic meter of water.
Most hydropower accidents have fallen in small and medium projects.
The Central Power Corporation reported that the central region has a total of over 40 hydropower plants at a capacity of below 30MW each, which have come into operation. Of these only four were built by investors from the electricity industry. The remaining number was conducted by investors from other fields.
The environmental impact assessment of these projects were disregarded or ignored. Lax management and supervision over construction process has worried people in low lying areas.
Chief of the Flood and Storm Prevention Steering Committee in Thua Thien-Hue province Phan Thanh Hung said that most hydropower projects in the central and Central Highlands regions have not built dam breach scenarios as per regulations at Decree 72.
Delegates at a forum in Hue City in October pointed out another problem that most hydropower projects in the two regions have not replanted forests in return for chopped down areas. Only few have done so with an inconsiderable area.
VNS/SGGP/VNN

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