In late April each year, not only the beautiful natural landscapes attract many eyes to Dongchuan, Yunnan, but also the thrilling China·Dongchuan Mudslide International Off-Road Race. Off-road enthusiasts from all over the country bring their cool off-road vehicles here, lining them up on the streets of Dongchuan.
Located near the famous Xiaojiang Fault Zone, the Dongchuan area has historically been shunned due to frequent mudslides during the rainy season. However, in safe seasons, these mudslide-impacted beaches gradually become an arena for adventurers. Utilizing its unique geomorphological resources, Dongchuan has successfully transformed itself into a world-renowned cultural and tourism brand, a transformation inseparable from the scientists at the Chengdu Institute of Mountain Hazards and Environment of the Chinese Academy of Sciences.
Not long ago, the mention of mudslides in Dongchuan from the last century would change colors. Today, Dongchuan has managed to turn a past disaster crisis into a cultural tourism opportunity, thanks to the relentless efforts of the Chengdu Mountain Institute’s research team for 62 years here. They have conducted long-term observation, research and prevention work in Dongchuan, providing reliable scientific support for the prevention and management of mountain hazards.
This April, Dongchuan kicked off a new round of scientific progress. The world-class scientific facility, “Large-Scale Dynamics Simulation Platform for Mountain Hazards,” was activated here, further strengthening the ability to reveal the laws of mountain hazards and solve practical problems. Off-road racers and researchers, one challenging natural tracks, the other climbing the peaks of science.
The renowned case of Dongchuan, Jiangjiagou, is lauded as a pearl of the Xiaojiang basin. It is frequently active with mudslides and is known as the “World Mudslide Natural Museum” due to its unique geological phenomena. Standing beside the gully, overlooking the continuous mountains, and looking down at the gray-white riverbed below, one can seemingly feel the power and beauty of nature.
The Chinese Academy of Sciences Dongchuan Mudslides Observation Research Station and the Large-Scale Dynamics Simulation Platform for Mountain Hazards are situated on this magical land. On the platform, researchers can carry out more precise simulations and studies on mudslide activities. Its complex facilities and precise geographic location aim to simulate an experimental environment as close to natural conditions as possible.
The spillway of the experimental platform is one of its core components, approximately 150 meters long, and aims to provide an environment that simulates the occurrence and movement of mudslides. Scientists can unleash nature’s power here to observe, analyze, and learn everything about mudslides, helping people better predict and prevent potential natural disasters.
The experimental platform is not only capable of simulating mudslides but also landslides, mountain torrents, barrier lakes, and other mountain hazards. These simulations mainly aim to gain a deep understanding of the formation, initiation, and movement mechanisms of disasters, so as to clearly recognize the development process of the disaster chain.
At the 32° spillway slope area of the experimental platform, researchers focused on observing and studying the formation process of disasters. In the 16° slope area, they paid attention to the movement process of the disaster. In addition, the platform also has a horizontal embankment platform of about 2,500 square meters, which is dedicated to studying the accumulation and impact force of mountain disasters, which is particularly important for the safety testing of disaster prevention and mitigation engineering and products.
Compared with the existing dynamic simulation experimental devices at home and abroad, this experimental platform has achieved an order of magnitude improvement in terms of experimental scale and motion distance. Compared with similar devices internationally, it has many advantages such as large scale, repeatable experiments, and controllable experiments, and has reached the world-leading level in the following three aspects: it is the largest physical simulation experimental platform for mountain disasters in the world, with the highest degree of automation monitoring and the best synchronicity of data collection.
In terms of physical simulation scale, the platform can discharge up to 500 cubic meters of materials, and the entire process from discharge to the completion of the experiment takes only about two minutes. During this period, the built-in comprehensive monitoring system can quickly and accurately capture the key information of the entire dynamics process.
The spillway is divided into three observation sections, each equipped with a variety of detection technologies such as sound, light, electricity, magnetism, and heat. There are a total of 9 sets of equipment in the spillway, each set including cameras and high-speed cameras, and induction modules are buried under the concrete bottom slab at the bottom of the spillway. Under the horizontal embankment, 5 sets of base sensors are installed, and all synchronously collected data are gathered to the data collection room located at the top.
The experimental platform is also equipped with distributed fiber-optic sensors, which can achieve millisecond-level error in sensing speed. To address the international frontier scientific issues of turbulent dynamics and particle material kinematics, especially the complex particle material problems of mountain disaster bodies, this experimental platform was established. Research on the scale effect of the movement of multiphase media of particulate materials in nature requires the support of larger-scale scientific facilities and experimental platforms.
The establishment of this experimental platform is essentially to reveal the laws of nature. This has been consistent since the establishment of Dongchuan Station in 1961, through the efforts of generations of scientists. During the hazardous period every year (May to September), researchers bravely go into the mountainous areas where debris flows occur frequently for long-term field investigation and research, adopting the work mode of “must enter the mountains during the rainy season, must explore trenches when in the mountains, must wade in the water when exploring trenches, and must stay longer when wading.”
Debris flow disaster investigation and research often involve various considerations, including the measurement of key data such as flow velocity, flow rate, and sludge height. These tasks rely on advanced tools such as radar velocimeters, floats, and ultrasonic mud level meters. However, when there is a lack of sufficient automation equipment, researchers have to invest a lot of time and energy in sampling, sometimes working for several hours continuously under the scorching sun or during thunderstorms at night.
In extreme conditions, the sampling work during a power outage is even more difficult, requiring researchers to personally carry iron buckets to the site to manually collect debris flow samples. For safety, samplers also need to tie ropes so that their companions can rescue them. Recalling a dangerous incident in 1989, a researcher was almost swept away by a debris flow during the sampling process, and it was the timely response of his companions that averted the tragedy.
Based on Dongchuan Station, the Chengdu Institute of Mountain Research has accumulated a large amount of data on the various sections of the upstream, midstream, and downstream debris flow as well as the evolutionary process of riverbed deposition through years of observation and research. Currently, this valuable database has reached over 300GB, with more than 700 applications per year to use these materials. Researchers who have access to this precious data then delve into exploring the formation mechanisms and dynamic processes of mountain disasters through analysis and simulation experiments.
Due to the limitations of stability and repeatability of on-site experiments, and limitations of indoor simulation equipment conditions, the research team conceived the idea of establishing a large-scale debris flow field model experimental site. This ambitious idea had been brewing since 2002, but due to various issues such as economic resources and land procedures, the plan was delayed in implementation.
It wasn’t until 2015 that the huge-scale mountain disaster dynamics simulation platform was officially put on the agenda and began to move forward. Under the leadership and guidance of the Chinese Academy of Sciences, the Chengdu Institute of Mountain Research, the Hong Kong University of Science and Technology, and China Electric Power Construction Group cooperated to carry out the project, aiming to build a world-class experimental platform with a service life of 30 years. After 8 years of meticulous planning and construction, the experimental platform began trial operation in December 2023 and was officially put into use in April thereafter.
At a strategic advisory meeting on disaster prevention and mitigation, Cui Peng, the former station chief of Dongchuan Station and an academician of the Chinese Academy of Sciences, emphasized that research work should not only publish academic papers but also focus on solving practical problems. His concept is that experimental research should not only pursue innovation (“reach the sky”), but also ensure that the results can solve actual disaster problems (“stand on the ground”).
In the past, the Dongchuan Station research team devoted itself to establishing a prevention and control system that combines scientific research with practical needs. Through cooperation with the local government, they proposed the “Dongchuan Model” that integrates engineering and biological control, prevention, and development. Innovatively carrying out debris flow prevention and control work, they implemented comprehensive prevention measures such as stabilizing soil, constructing sediment control dams, managing water resources, and developing arable land.
According to Mr. Chen Shunli, downstream of the debris flow-prone areas, a debris flow diversion channel named “Dongchuan Channel” was constructed. This innovative project greatly directed debris flows toward areas with less environmental hazard, achieving comprehensive management of debris flow disasters. The implementation of this set of comprehensive management measures not only successfully reduced the threat of disasters but also transformed barren lands into fertile grounds and even promoted the emergence of new cultural tourism industries.
Looking to the future, with the aid of heavy simulation equipment, where will the “Dongchuan Model” go? Deputy Director Chen Xiaoqing pointed out that the newly built experimental platform can simulate mountain disasters at near prototype scale, which is crucial for quickly grasping its influencing factors and internal laws. Additionally, the platform will also be used to test disaster prevention and mitigation projects and products, and thereby establish corresponding safety technical standards, making prevention and control work more scientific and systematic.
Chen Xiaoqing believes that in the face of the task of constructing an ecological civilization, the new generation of scientific researchers should adopt the concepts of “green sustainability” and “enhanced resilience” as their direction of exploration. Forebears, in the context of limited resources, went through decades of groping and practice to devise an effective “Dongchuan Model.” Modern scientific workers, with the advantage of these advanced experimental platforms, could in a shorter amount of time create a more innovative “Dongchuan Model,” thus providing more robust scientific and technological support for prevention and control efforts.