On May 15th, 2021, the Tianwen-1 lander landed in the southern part of the Utopia Plain of Mars. "Steady!" Jiang Mingjing, who stood in front of the TV, saw the news and stood up from his chair excitedly, holding his fist and cheering.
This report three months ago gave the reporter the idea of interviewing Professor Jiang Mingjing from the School of Architecture and Engineering of Tianjin University. During these three months, the reporter contacted him many times. As a result, Professor Jiang was either on a business trip or on his way. The background of several calls was the voice of the plane broadcast urging him to turn off his mobile phone. Professor Jiang’s busyness made reporters both surprised and helpless, and even had the idea of giving up the interview. Finally, these days, Professor Jiang returned to Tianjin to tutor graduate students, and the reporter seized this "hard-won" opportunity.
According to the report, in order to make Tianwen-1 land smoothly, Jiang Mingjing and his team spent two years simulating the construction of a Mars surface in Huailai County, Hebei Province. Mars, which is tens of millions of kilometers away from the earth, is an unknown field that needs to be explored urgently. It sounds impossible to "move" it to the earth, but Jiang Mingjing succeeded.
"My major is studying’ soil’, and all kinds of’ difficult soil’, such as Mars’ soil, are actually only a small part of my research content." Jiang Mingjing, a native of Jiangsu Province, speaks an authentic "soft language of Wu Nong". It never occurred to him that the tenderness and delicacy of the water towns in the south of the Yangtze River cultivated such a "hard-core" professor who was willing to deal with clods and stones.
"I studied undergraduate in 1982 and have been engaged in geotechnical research for more than 30 years." Looking at Jiang Mingjing’s resume alone, there are nearly one page: Professor, Doctoral Supervisor, Department of Civil Engineering, School of Architecture and Engineering, Tianjin University; bachelor’s degree and master’s degree in engineering from Hohai University in 1986 and 1993, and doctor’s degree in engineering from nanjing hydraulic research institute in 1996. In 1998, he was a special researcher at Osaka Institute of Soil Testing (now Japan Institute of Regional Site Environment); in 1998-2000, he was a special researcher at Kyoto University in Japan; in 2000-2003, he was a postdoctoral fellow at Lavalle University; in 2003-2004, he was a postdoctoral fellow at the University of Nottingham in the United Kingdom; in 2004-2006, he was a professor at Tongji University School of Civil Engineering. Since 2018, he has been a professor and vice president of the School of Civil Engineering of Tianjin University. Since 2010, he has served as the vice chairman of TC105 Committee of the International Association of Soil Mechanics and Geotechnical Engineering (reelected), won the National Natural Science Outstanding Youth Fund in 2009, and was selected into the National Million Talents Project in 2014. The 22nd Huang Wenxi Lecturer, a highly cited scholar in China published by Elsevier (2019 and 2020), and a top 2% scientist in the world published by Stanford University (2020). Experts from the Advisory Committee of the Ministry of Industry and Materials of the National Natural Science Foundation, experts from the Water Conservancy Association, experts from the National Natural Science Award, and young and middle-aged experts who have made outstanding contributions to the country.Enjoy the special post of the State Council government …
There is no need to say anything about the difficulty and gold content of a doctor more than 30 years ago. "At that time, the scientific research conditions were really bad, but the overall academic atmosphere was very positive. Everyone was engaged in research and everything was for scientific research." Jiang Mingjing said that he was lucky to meet a group of good teachers, which not only pointed out the direction for him, but also paved the way for his future scientific research. "When I was studying for a master’s degree, my teacher applied for an exam-free PhD and advanced placement for me, which was unprecedented. At that time, it was the only one in our school." During Jiang Mingjing’s Ph.D. study, the personal research funds totaled only 6,000 yuan in three years. "Although the price was low at that time, it was still far from enough. The teacher took out his funds from the National Natural Science Foundation and made a special application for me. A total of 45,000 yuan was spent on my research projects."
Shoulder the heavy responsibility and live up to expectations. It used to be a worldwide problem to simulate large voids in structural soil. Through analysis, Jiang Mingjing thinks that adding ice particles into soil materials at low temperature can artificially form large voids, and finally the structural soil can be artificially prepared. For this reason, he made a detailed experimental design, which was quickly recognized by the teacher. Although the idea is good, where can we find such a low temperature environment? Until Jiang Mingjing saw the cold storage in the school canteen. "I told the teacher that I have found a way to do the experiment, but I have to trouble you to say hello to the school logistics department."
I heard that Dr. Jiang was going to do the experiment, and the logistics readily "gave the green light". Nanjing in midsummer is as hot as fire, just like Jiang Mingjing’s mood of looking forward to the experiment. "In order to do a good job in the experiment, we made all kinds of preparations as comprehensively as possible, such as equipment, cotton trousers, cotton-padded jacket … that day, we were all very excited, but we were dumbfounded as soon as we entered." The young student was ready for the experiment, but forgot to be mentally prepared-the cold storage belongs to the canteen, and all kinds of "animals" are completely frozen inside. "It’s funny to think of it now, but at that time, several classmates and I were scared to have nightmares at night."
The cold storage experiment was successful, and Jiang Mingjing pursued the victory. "As long as I am engaged in scientific research, I will always be full of combat effectiveness." In order to get the data as soon as possible, he kept his hands on the experimental equipment. The air compressor was used in the experiment, which was very loud, especially in the dead of night. "I am used to it myself, that is, I suffered the residents nearby. At first, some people reported to the director. Later, when everyone knew that they were doing the experiment, they all expressed their support and understanding. I am very moved by it in retrospect."
Thick accumulation can make thin hair. Jiang Mingjing’s research achievements have attracted wide attention in the world. He has not yet graduated from a doctor, and many world-renowned universities have sent him warm invitations. At the beginning of 1998, he went abroad and worked as a postdoctoral researcher in Osaka Soil Experimental Institute, Kyoto University, Lavalle University, Manchester University and Nottingham University. In 2006, with the belief of serving the motherland, he resolutely returned to Tongji University to teach.
During the interview, the reporter always had a feeling that scientific research was not a career for Jiang Mingjing, but a belief, a belief engraved in his bones and willing to follow him all his life. Like, love, obsession … These are not enough to describe his persistence in scientific research. "When I first returned to China, the salary I got a month was only 1,500 yuan, and the rent was 1,850 yuan. For a long time, I was supplemented by my previous savings."
The firm belief has brought Jiang Mingjing to this day step by step, and time has proved it best. In recent years, with the continuous strengthening of China’s comprehensive strength, the scientific and technological strength is also making rapid progress. Aerospace, deep-sea exploration … These sophisticated fields have left more and more China and China footprints. During this period, Jiang Mingjing and his team also undertook project research in many related fields. "In addition to the Martian soil just mentioned, the deep-sea soil is also the focus of our research in recent years. Recently, we are preparing to carry out exploration, development and environmental protection of combustible ice and other resources in Hainan. "
Adhere to the problem-oriented and face the major needs of the country. As an expert and scholar in the field, Jiang Mingjing is well aware of our current shortcomings and weaknesses. "Some key technologies, important equipment, new energy technologies and other fields that are related to the urgent needs and long-term needs of the country must be in our own hands, so we must speed up the pace and work hard in this direction."
From Jiang Mingjing’s words, the reporter can strongly feel his urgent and expectant mood. From a grain of sand to a piece of soil, from a mountain to a star, Jiang Mingjing has always closely linked scientific research with actual needs. Knowing the heavy responsibilities, but having the courage not to be afraid of failure; I also know that the road is far, and I still have the enthusiasm to concentrate on research.
At the end of the interview, the reporter asked Professor Jiang if he expected to visit space in the future. The professor smiled and said, "Of course! Space travel has been realized, which is not far from us. " Only after the hardships of being down-to-earth can we have the courage to look up at the stars. Similarly, we also expect Professor Jiang Mingjing to lead us to see a higher and further world with his scientific research achievements.
Exclusive dialogue
Reporter: Can you briefly introduce your research field?
Jiang Mingjing: My research field is soil mechanics, which is an applied discipline to study the stress-strain or stress-strain-time relationship and strength of soil under the action of force. It is a branch of engineering mechanics. The research object of soil mechanics is soil and soil closely related to human activities, including artificial soil and natural soil, and groundwater closely related to the mechanical properties of soil. Soil mechanics is widely used in the design of foundations, retaining walls, geotechnical structures and dams, and is an important branch of engineering disciplines such as civil engineering, geotechnical engineering, engineering geology and energy engineering.
The development of soil mechanics should be initiated by Coulomb, which can be roughly divided into three historical stages: germination period (1773-1923), classical period (1923-1963) and modern soil mechanics (1963-present). Modern soil mechanics is a system based on macroscopic test results, continuum mechanics method and macroscopic constitutive theory of soil, and numerical analysis methods such as finite element and finite difference are used as tools, which plays an important role in geotechnical engineering practice.
At present, with the continuous expansion of geotechnical engineering in space, especially the promotion of deep, deep-sea and deep-space engineering ("three-deep engineering"), researchers and engineers need to face more complex environmental conditions (high geostress, high/low temperature, high water pressure, high vacuum, low gravity, strengthening chemical action, etc.) and difficult geotechnical materials, such as structural soil (temperature, pressure and force coupling, T-
Reporter: After successfully completing the Mars exploration project, what is your current research focus?
Jiang Mingjing: Recently, I am mainly engaged in deep-sea engineering projects. With the rapid development of China’s coastal economy, the proposal of the "Belt and Road Initiative" and the promulgation of the "Thirteenth Five-Year Plan" for the development of the national marine economy, offshore engineering projects such as offshore wind power, cross-sea bridges, submarine tunnels, offshore oil drilling platforms, seawater power generation, submarine pipeline laying, land reclamation and marine nuclear energy are constantly increasing, and offshore engineering projects are constantly growing and enriching. Ocean engineering has changed from traditional engineering projects to new engineering projects, and gradually developed from offshore and shallow sea to far sea and deep sea. The scale of the projects is also expanding, which puts forward higher requirements for the sensitivity, safety and durability of ocean engineering. A series of marine resources development is accompanied by many engineering and technical problems that need to be solved urgently, such as the safety of mining platforms and submarine optical cables, and the early warning and mitigation of natural disasters such as submarine earthquakes and seabed landslides are also the core issues of global concern.
Taking the exploitation of deep-sea natural gas hydrate resources as an example, the decomposition of hydrate will inevitably lead to the deterioration of the mechanical properties of the seabed, and improper exploitation methods may induce large-scale disasters (such as landslides) or the collapse of pile foundation platforms. How to choose a safe mining mode and area to reduce the impact of mining activities on the marine environment has become the primary problem in the actual hydrate mining process. It is very difficult to conduct on-the-spot investigation and research on the seabed, and it is expensive to simulate the deep-sea environment by laboratory tests. Therefore, we need to strengthen scientific research and comprehensively analyze the promotion of marine engineering to ensure its safety and feasibility.
Reporter: After listening to your introduction, we probably know the practical application of soil mechanics. What are your professional opinions on the future development opportunities in this field?
Jiang Mingjing: A new key field of soil mechanics has emerged-macro-micro soil mechanics. In the past 40 years, macro-micro soil mechanics has experienced germination, embryonic form and growth period, so it can be said that it is now welcoming the stage of accelerated development. I think the development opportunities of macro and micro soil mechanics in the future mainly include the following four aspects.
The first is to establish an efficient calculation method suitable for various geotechnical engineering problems. The research in this field may involve the physical and mechanical mechanism on the molecular or nanometer scale, and it also needs efficient coupling calculation methods. Because hundreds of millions or even trillions of particles need to be calculated, this will require high computing power. With the rapid development of computer technology, this contradiction will gradually weaken.
Secondly, according to the real working environment, the model of the difficult rock and soil mass of the "Three Deep Projects" and the relationship between the structural evolution and the macro-characteristics are established. The research in this field not only needs the micro-and micro-scale experimental technology to simulate extreme environments such as high/low temperature, high water pressure, high vacuum and chemistry, but also needs to solve the contradiction between the scale effect of representative units and the limitation of experimental testing accuracy, and also needs to develop the extraction, processing and analysis technology of micro-and micro-structural information in three-dimensional soil. However, with the development of multifunctional, high-precision and large-range X-ray CT, these problems are expected to be solved step by step.
The third is to establish a practical theoretical model, and solve all kinds of complex and difficult core problems in geotechnical mechanics and engineering of "three deep projects" to help improve the engineering design level. In different geotechnical engineering problems, the stress path experienced by soil is different, so it is difficult to accurately obtain the stress path and mechanical properties of undisturbed soil in the field by current geotechnical testing technology. Therefore, it is a research idea to establish a practical constitutive model by using appropriate methods for simulation and corresponding indoor experimental research.
Fourth, the four branches of macro-micro soil mechanics and modern soil mechanics and the cross-development of other disciplines. Macro-micro soil mechanics can not only cross theoretical soil mechanics, computational soil mechanics, experimental soil mechanics and applied soil mechanics in this discipline, but also cross other disciplines, such as rock mechanics and near-field dynamics in mechanics disciplines. This will not only contribute to the self-development of macro-micro soil mechanics, improve modern soil mechanics, but also promote the rapid development of other disciplines.
In a word, macro-micro soil mechanics has become one of the most dynamic research directions, and its accelerated development period is coming soon. To this end, we need the participation of many young scholars with solid foundation and prime of life, as well as the care and support of senior researchers who have been fighting in the front line of scientific research for a long time and have a deep understanding of difficult and key problems in geotechnical engineering.
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(Editor Liu Xiaoyan Han Jingfeng)
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