The N-J Hydropower Project in Pakistan is a major energy project on the China-Pakistan Economic Corridor and the largest hydropower project under construction in Pakistan. Due to its special strategic location and power supply status, it is known as "Pakistan's Three Gorges Project".
Located in the Himalayan region, the project is in a typical high-stress tectonic zone. During tunnel boring machine (TBM) construction, rockbursts occurred frequently, causing great harm to construction personnel and equipment.
To solve the world-class problems encountered in the project, scientists and engineers from many countries have successively participated in the construction. Among them is a Chinese research team—the Feng Xiating team from the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. This year, the researchers gave up the opportunity to reunite with their families during the Spring Festival and silently contributed China's scientific and technological strength to reduce the hazards of rockbursts.
Facing Challenges Head-On
On the eve of the Lantern Festival, amid the bustling crowd at Beijing West Railway Station, the reporter met the travel-stained researcher Chen Bingrui. He had just come out of the deep mountains of Pakistan and, after a long bumpy ride, transferred here to go home.
During the 2016 Chinese Monkey Year Spring Festival, the two diversion tunnels of the N-J Hydropower Project entered the most difficult stage. In order to allow the TBM to smoothly pass through the high-stress strong rockburst zone at great depth, Chen Bingrui, Feng Guangliang, Li Pengxiang, Tan Shuang and other researchers, under the arrangement of Feng Xiating, stayed at the front line of work to carry out microseismic monitoring and rockburst warning.
The Chinese team's connection with the N-J Hydropower Project began with an accident. The extremely strong rockburst that occurred on May 31, 2015 severely damaged TBM No. 696, worth nearly 300 million yuan, and it was shut down for repair for half a year. This not only caused great panic among on-site construction personnel but also brought enormous domestic and international public opinion pressure on the project construction.
After the incident, the Pakistani side searched worldwide for experts in rockburst monitoring, warning, and prevention. In June 2015, Feng Xiating's team received an invitation letter from the Gezhouba Group and immediately rushed to the project site.
After determining a detailed microseismic monitoring and rockburst warning plan, Feng Xiating's team equipped the two TBM tunnels with "stethoscopes"—microseismic monitoring systems—and began real-time "diagnosis"—rockburst monitoring and warning. At present, TBM No. 696 has resumed excavation, and TBM No. 697 has successfully excavated to the tunnel section with the greatest depth.
Persisting on the Front Line Despite Illness
Earlier, when the reporter contacted Feng Xiating by phone, he suggested that the reporter meet Chen Bingrui, who had just returned from Pakistan. At that time, he subtly said: "Chen Bingrui's health has not been good recently."
After years of training, Chen Bingrui has long become a technical backbone of the institute. He has long been engaged in front-line work on major domestic and international rock engineering projects, conducting research on microseismic monitoring technology, analysis and warning methods, disaster incubation mechanisms, and protection for the incubation process of rock engineering disasters. Around his research direction, he has led several national projects.
Before the New Year, when Feng Xiating went to the project site, he found that Chen Bingrui had stuffed a ball of cotton into his nostrils, trying not to let it show. It turned out that since 2013, Chen Bingrui had been diagnosed with low platelets. He often had nosebleeds and might face the risk of internal bleeding in organs. In such a harsh environment, he could only rely on medication to endure.
"Returning to China this Lantern Festival, on the one hand I want to see my father, and on the other hand I need to see a traditional Chinese medicine doctor," Chen Bingrui said. But his vacation was only three days, and then he had to return to the institute.
Overcoming Difficulties with Dedication
According to reports, the N-J Hydropower Project has two TBM construction tunnels and uses two sets of microseismic monitoring systems: one from South Africa and the other independently developed by the Institute of Rock and Soil Mechanics. Competing on the same stage with equipment from a veteran South African microseismic monitoring manufacturer is a highly stressful challenge. Moreover, every step of the on-site work had to be "watched" by supervisory engineers from the American company Hazra.
The supervisory engineers always came with a lot of questions, "picky" about every technical detail. In this situation, "do it well if you do it" became the creed that encouraged everyone to brace up and meet the challenge. They patiently explained to these "competitive" foreigners time and again, and finally gained their recognition at all levels.
The challenges did not end there. Although they had rich experience in rockburst warning and were psychologically prepared for rockbursts, the cruelty of actual work still occasionally struck their hearts.
On February 10, the third day of the Chinese New Year, Chen Bingrui and his teammates were installing sensors and overhauling equipment in Tunnel 697 as usual. Suddenly, a moderate-intensity rockburst occurred less than 2 meters ahead of them. Fortunately, this rockburst was within their warning range, and the construction unit carried out systematic support, so there were no adverse consequences.
The reporter learned from Feng Xiating that other scientific and technical personnel in the team are still fighting on the front line of the project, preparing to overcome the next technical difficulty.