On the 50th anniversary of graduation, I have also been engaged in soil mechanics for 50 years. Since retiring in 2007, I have continued to write: compiling textbooks, writing articles and monographs, giving lectures and presentations, and providing review and consultation services. I have thus fulfilled President Jiang Nanxiang's requirement to "work healthily for 50 years."
　　My connection with soil mechanics runs deep. When I studied at Tsinghua University's Department of Water Resources, our soil mechanics teacher was Mr. Chen Liangsheng, a Harvard University PhD who studied under Professor Casagrande, and Casagrande was a disciple of Terzaghi. Thus, tracing the lineage of martial arts schools, I should belong to the direct line of Terzaghi.

Two Harvard alumni—Mr. Chen Liangsheng and Mr. Lu Zhaojun

　　In the early 1960s, China also had a graduate education system, with a program of about 3 years and no degree, roughly equivalent to the Soviet "Candidate of Sciences." At that time, Tsinghua implemented an extracurricular learning and training format called "teaching students according to their aptitude" for undergraduates. Students who studied more easily and had better grades could apply for the subject they were interested in, roughly equivalent to a probationary graduate student. I remember that our grade had three soil mechanics students under this program: Li Guangxin, Chen Zuyu, and Hu Jintao. Under Mr. Chen Liangsheng's guidance, we conducted many experiments. At graduation, the "Cultural Revolution" broke out, and we were all swept out together, and our dream of becoming graduate students was shattered. The photo below is our class graduation photo. Because of this connection, in "50 Lectures on Geotechnical Engineering," I once teased this old classmate about the mistake of "consolidating the foundation."

  

　　The location in the photo is the Second Gate of Tsinghua University. Because the Second Gate was considered feudal and capitalist, it was demolished at that time and replaced with a statue of the great leader. In the second row, second from the right, is Professor Li Guangxin; in the third row, second from the left, is General Secretary Hu Jintao.
　　In 1968, I was assigned to Hulan County, Heilongjiang Province. After a brief few months working at the Water Resources Bureau, I was sent to the "May 7 Cadre School" for re-education and training. Trusted by the leadership, I was appointed vice principal of the cadre school (deputy company commander). Less than half a year later, the Zhenbao Island crisis occurred, and to transport war preparedness materials, a emergency bridge was to be built over the Hulan River. So I was urgently transferred to the bridge construction command. On April 20, a week after the ice thawed, after drinking a large mug of baijiu, we went into the icy river to set pile positions. Then I alone was responsible for the construction of 24 piles for a 7-span double-curved arch bridge. At that time, there was no so-called engineering investigation; we used a "large pot cone" manual drilling rig for underwater drilling. Each time a sample was brought up, I had to check whether it was coarse sand, medium sand, or gravelly sand, judge its relative density based on the drilling resistance, then check its friction resistance, and add it up segment by segment. When the safety factor reached 2.0, I ordered drilling to stop, lowered the tremie pipe, and poured concrete. In this way, I worked continuously for several days and nights. During the Cultural Revolution in the 1960s, a bridge of more than 333 meters was completed in just over a year under conditions of shortage of manpower and materials and winter construction, and it has now been in use for 46 years. Wouldn't this make today's fragile bridges ashamed?

　　By 1978, I had been working in Hulan County for 10 years, always building embankments and dams, digging ditches and draining waterlogged areas. From survey team leader and engineering group leader to deputy director of the Water Resources Bureau, and just as I was being considered as a candidate for county deputy magistrate, the graduate education system was restored, and I decided to apply for graduate school at Tsinghua. At that time, the leadership talked to me, and I thanked Hulan County for its kindness, but I still wanted to take the graduate exam. Having drifted in the outside world for more than ten years, I only had a copy of "Hydraulic Structures" on hand, so I applied for the hydraulic engineering major. Six people went to the interview, but only five were admitted to hydraulic engineering. I heard that no one had applied to Mr. Huang Wenxi in soil mechanics, and I heard that Mr. Zhang Guangdou in hydraulic engineering was very fierce, while Mr. Huang was very kind. So I wrote to Mr. Huang, explaining that I had been a student in soil mechanics under the aptitude-based program, and that due to the Cultural Revolution, when I left school, my soil mechanics textbook was lost and I could not review, so I hoped to transfer to the soil mechanics major. Since my score ranked first among more than 100 candidates, Mr. Huang gladly accepted me as his only disciple. I should state here that later, Mr. Zhang's graduate student was in the same room as me, and in fact Mr. Zhang was also very good to his graduate students, but sometimes pretended to be fierce—a very lovable old gentleman.
　　So I studied at Tsinghua University under Mr. Huang Wenxi. The old gentleman was sincere and warm, like a spring breeze. Being his student was pleasant but never easy. As soon as I started the research topic, Mr. Huang required me first to read intensive 100 English papers on soil constitutive relations; then, starting from developing instruments, to complete three sets of tests: constant p triaxial tests, true triaxial tests, and hollow cylinder tests simulating a pressuremeter; then to compile finite element programs using six constitutive models and compare and verify them with the tests. From elementary school to university, I had studied Russian, and only started learning English from ABC at nearly 40. Reading 100 papers on "constitutive relations," probably the most academically difficult topic in soil mechanics, plus the language barrier, the difficulty can be imagined. I had to hold a dictionary in my left hand and a pen in my right, and gnawed through them one by one. At that time, photocopying was an unattainable luxury, and all figures in the articles were accurately traced by hand. I have kept more than ten such hardcover notebooks.
　　In addition to self-study, the teaching and research group also gave me classes. Besides Mr. Huang Wenxi often giving me "single-trough feeding," teachers like Mr. Chen Zhongyi, Mr. Pu Jialiu, and Mr. Li Jingkun often took turns giving me, their only student, classes for a whole morning. This kind of treatment of having many teachers in one lifetime is rarely enjoyed by people today.

 

　　China's first batch of geotechnical engineering PhDs defended their dissertations successively between 1983 and 1985. The first batch of geotechnical engineering PhDs in China included Gong Xiaonan, Zhang Daokuan, and Li Guangxin, whose supervisors were Mr. Zeng Guoxi, Mr. Lu Zhaojun, and Mr. Huang Wenxi, respectively. Later, Zhang Daokuan passed away young. Among the three, I was the last to defend, which is related to the fact that I was then in charge of the department's graduate work and was an "on-the-job" student. Calculating, my student career totaled 27 years: 6 years of primary school, 6 years of middle school, 6 years of undergraduate study (actually 8 years, because during the Cultural Revolution I stayed at school to "make revolution"), 3 years of master's, and 4 years of doctoral study. The so-called 50 years of healthy work actually has to be discounted.
　　My doctoral dissertation title was "Discussion and Model Verification of Three-Dimensional Constitutive Relations of Soil." I remember that my original proposed title was "Research and Model Verification of Three-Dimensional Constitutive Relations of Soil." Mr. Huang changed it to "Discussion," which shows the old gentleman's academic humility in the boundless ocean of knowledge. I remember that at that time, 100 copies of the dissertation were sent out for comments, and more than 80 replies were received. The experts participating in the defense included Mr. Huang, Mr. Lu Zhaojun, Mr. Zhou Jing, Mr. Shen Zhujiang, Mr. Wang Zhenghong, and Mr. Chen Yujiong. The dissertation defense resolution included the comment "reaches the level of outstanding doctoral dissertations of famous international universities." Later, it was rated as an outstanding doctoral dissertation of Tsinghua University, and I received the "Degree Recipient with Outstanding Contributions" award issued by the Academic Degrees Committee of the State Council and the State Education Commission.

 

 Badge for Chinese Degree Recipients with Outstanding Contributions

　　I have been hesitating forward on this small path of soil mechanics for 50 years. If I had been willing to manage my career, I might have had a brilliant official career; if I had been willing to lower myself, I might have had great fame. But the poplar flowers did not borrow the east wind's power, and in this life I have never sought favors from others. I remember that when congratulating Mr. Huang Wenxi on his 90th birthday, I presented a poem, and now I only remember the lines "I often admire the integrity of pine and cypress, and even more admire the depth of knowledge like rivers and seas." If the gentleman is a pine or cypress, I am just a white poplar, but equally upright; if the gentleman is a river or sea, I am just a pond, but equally clear. In this field, I have been fortunate to receive the cultivation and guidance of many famous teachers and masters, and I should strive to make some contributions. Looking back, I restarted the China Geosynthetics Engineering Association and helped this cause develop healthily; I founded the Soil Mechanics Teaching Committee, and the seminar held once every 23 years has also been very effective; I have written three textbooks, two popular science books, and one "Ten Lectures." Although simple, they are still thorough. Such a life should be wonderful.