Abstract: He created the "Golden Formula" in the field of geotechnical mechanics research in China, enabling China's deep foundation pit engineering design to stride forward from "learning from the West" toward Chinese-style modernization; after more than 20 years of research, the theory he proposed achieved a new breakthrough in a century-old problem of soil mechanics theory and drove a transformation in foundation design; he has participated many times in flood-fighting and disaster-relief work within and beyond the province, safeguarding major engineering safety and flood-control emergency operations. He is Yang Guanghua, a recipient of the 7th "Nanyue Craftsman" award and Honorary President of the Guangdong Research Institute of Water Resources and Hydropower.

Yang Guanghua

He created the "Golden Formula" in the field of geotechnical mechanics research in China, enabling China's deep foundation pit engineering design to stride forward from "learning from the West" toward Chinese-style modernization; after more than 20 years of research, the theory he proposed achieved a new breakthrough in a century-old problem of soil mechanics theory and drove a transformation in foundation design; he has participated many times in flood-fighting and disaster-relief work within and beyond the province, safeguarding major engineering safety and flood-control emergency operations. He is Yang Guanghua, a recipient of the 7th "Nanyue Craftsman" award and Honorary President of the Guangdong Research Institute of Water Resources and Hydropower.

He created the "Golden Formula" in the field of geotechnical mechanics research in China

"As a researcher, I hold the dream of a scientist, always thinking about creating something useful to leave to future generations!" Yang Guanghua has for decades rooted himself in the engineering frontline, writing his papers on the land of the motherland. With the craftsman spirit of dedication, focus, and innovation, he has made outstanding contributions to the innovation and engineering application of modern soil mechanics theory, creating the "Golden Formula" in the field of geotechnical mechanics research in China.

"I hope that one day the theories or formulas I create can be written into textbooks and become formulas applied by everyone, like Newton's formulas, playing a role in the progress of human society!" Driven by this belief, Yang Guanghua encountered the most unforgettable engineering challenge of his life—the foundation pit support project for the construction of the Guangzhou Pearl River Crossing Tunnel.

Deep foundation pit support refers to the measures of shoring, reinforcement, and protection applied to the side walls of deep foundation pits and the surrounding environment to ensure the safety of underground structure construction and the environment around the pit. In the past, the design of deep foundation pit support engineering mostly adopted traditional foreign calculation methods, which could not fully calculate the true stress state and deformation of the support structure, seriously affecting the scientificity and safety of the design. Therefore, how to improve the calculation methods for deep foundation pit support engineering has long been a major problem troubling academic circles at home and abroad.

In 1989, during the construction of the Guangzhou Pearl River Crossing Tunnel, the deep foundation pit support project faced the test of complex and variable geological conditions and unprecedented design depth; at that time there were no precedents or standards for such projects in China. Yang Guanghua, a young geotechnical engineer participating in this project, after multiple site investigations, consulting domestic and foreign materials, and repeated deliberation, proposed a new incremental calculation method, which smoothly solved the difficult problem of complex stress calculation in deep foundation pit support design and was successfully applied to the engineering construction at that time.

In practice, this incremental calculation method continued to mature. In 1991, Yang Guanghua first published an article on the application of the incremental method; the Guangzhou Metro, starting from Line 1, fully applied this calculation method in foundation pit support engineering design, and it subsequently developed into a new systematic, advanced, and practical calculation method, becoming the main calculation method for deep foundation pit engineering design in China, known as the "Golden Formula."

Starting from this "Golden Formula," Yang Guanghua's theoretical system has been used in the design of thousands upon thousands of projects every year, greatly raising the design level of foundation pit support in China. At the same time, the incremental calculation method he proposed has also been incorporated into professional textbooks, monographs, codes, and commercial software such as the "Foundation Pit Engineering Manual" and "Deep Foundation Pit Engineering," playing a major role in engineering construction and academic research. Since then, China's deep foundation pit engineering design has strode forward from "learning from the West" toward Chinese-style modernization.

Yang Guanghua conducting a geotechnical triaxial test in the laboratory

He achieved a new breakthrough in a century-old problem of soil mechanics theory

Yang Guanghua explained that the design of major projects must carry out stress-strain calculation and analysis in advance to determine the safety and scientificity of the design, but the accuracy of the calculation depends on the correctness of the geotechnical constitutive model. Since a professor at Cambridge University established the famous Cambridge model in 1963, scholars around the world have established hundreds of models, yet none has been able to well solve this worldwide problem. The geotechnical constitutive model has become the most difficult and core scientific bottleneck in the development of modern geotechnical engineering science.

After more than 20 years of exploration, Yang Guanghua discovered and proposed a new theory to solve this problem—the generalized (plastic) potential theory. This theory breaks through the limitations of traditional plasticity theory and establishes a new theoretical system that includes the traditional theory as a special case and can better describe geotechnical characteristics. "This is an important pioneering achievement in continuum mechanics." Academician Zheng Yingren of the Chinese Academy of Engineering made this comment in the preface he wrote for Yang Guanghua's book.

The generalized (plastic) potential theory founded by Yang Guanghua has been widely recognized by peers; the theory has been incorporated into four graduate textbooks, including Tsinghua University's "Advanced Soil Mechanics," and three monographs, becoming the theoretical foundation of generalized plastic mechanics and promoting the development of the discipline. In engineering applications, it has been used in calculations for projects such as the deep-water cofferdam of the Three Gorges Project and other concrete face rockfill dams, providing more scientific theoretical support for engineering design.

Yang Guanghua is also a pioneer of new theories of modern foundation design, achieving new breakthroughs in problems that had lain dormant in soil mechanics theory for a century.

In foundation design, the calculation of foundation settlement and the determination of bearing capacity are the most basic classical problems in soil mechanics, a longstanding difficult problem that has not been well solved in the nearly one hundred years since the founding of soil mechanics; inaccurate foundation settlement calculation and unreasonable determination of bearing capacity will seriously affect project cost or safety.

After more than 20 years of research, Yang Guanghua proposed a new foundation settlement calculation method based on in-situ plate loading tests—the tangent modulus method—and a new method for determining foundation bearing capacity, achieving a new breakthrough in the century-old problem of soil mechanics theory and driving a transformation in foundation design, enabling foundation design to advance from strength-controlled design to the more advanced deformation-controlled design. It has been applied by many peers and in the literature, and has been verified and applied in the design of foundation treatment for projects with very high settlement control requirements such as the Wuhan-Guangzhou High-Speed Railway and the Hong Kong-Zhuhai-Macao Bridge. "It is an important advance in the development of soil mechanics as a discipline today," wrote Academician Sun Jun of the Chinese Academy of Sciences in the preface to Yang Guanghua's book.

He practices the original aspiration and mission of a "people's researcher"

With scientific research as his dream and practical application as his duty, Yang Guanghua, while solving key technical problems of major projects, also unswervingly practices the original aspiration and mission of a "people's researcher."

In 2005, the Xijiang River experienced an extraordinarily severe flood. The flood level on the river surface outside a county town in Guangdong exceeded the warning line, rising more than 7 meters above the streets. Under the strong flood pressure, the retaining wall protecting the safety of the county town shifted 2 centimeters, and multiple cracks bulged up on the street surface. If the retaining wall could not withstand the flood pressure and collapsed, the entire county town would be submerged, and the situation was extremely critical. In response, the local government organized large numbers of armed police, public security officers, and water conservancy cadres, ready at any time to organize the evacuation of affected residents.

"Is it necessary to organize a large-scale evacuation of the county town's residents? This was a major test facing the expert group fighting on the frontline of flood control and emergency rescue at that moment." Yang Guanghua led the expert group to inspect the site, analyzed the local geography and climate, the stress characteristics of the retaining wall, and historical data, and decisively judged that the retaining wall was safe and that a large-scale evacuation of the county town's residents was unnecessary. In the end, the retaining wall successfully withstood the impact of this flood, avoiding the major impact that a large-scale evacuation of residents would have had on the people and society.

Such tests are countless for Yang Guanghua. Over the decades, he has participated in emergency rescue at reservoirs during the Wenchuan earthquake, emergency handling and investigation of the Kangwang Road tunnel collapse in Guangzhou, the investigation of the major accident on Foshan Metro Line 2, and flood-fighting and disaster-relief work during the extraordinarily severe floods in Guangdong in 1998, 2005, and 2008 that exceeded once-in-a-century levels, safeguarding major engineering safety and flood-control emergency operations.

"In decades of work, I have hardly ever had a day off; often as soon as I think of a problem I forget my fatigue—perhaps this is the stimulant of scientific innovation!" Yang Guanghua said.

As a "scientist among engineers," he applies scientific and technological achievements to the great cause of realizing national modernization, opening an academic path never trodden by predecessors and realizing his scientific dream step by step. As a "researcher among the people," he plants his feet in the soil, writes his papers on the land, and devotes all his strength to serving the industry, the people, and the country, making tangible contributions to disciplinary development, engineering construction, and the protection of people's lives and property. He is truly a model of the times and a craftsman of the times.

● Craftsman's Words

● Reporter: What is your understanding of the craftsman spirit?

● Yang Guanghua: In my view, the craftsman spirit means identifying something beneficial to the country and the people, maintaining the focus of sharpening a sword for ten years, striving for perfection, and creating fine works that remain in the world to benefit society!

● Reporter: According to your understanding of the craftsman spirit, who is the "craftsman exemplar" you admire or would like to recommend to employees?

● Yang Guanghua: I recommend Li Bing, the builder of the Dujiangyan water conservancy project. Dujiangyan has stood不朽 for two thousand years—irrigating in times of drought and preventing disaster in times of flood. It not only successfully eliminated flood disasters but also solved the problem of agricultural irrigation water, creating the Land of Abundance. Under the scientific conditions of that time, being able to work out such an ingenious water-control plan and build a millennium project to benefit society vividly embodies the craftsman spirit of persistent focus, striving for perfection, meticulousness, and the pursuit of excellence.