Research Areas and Research Achievements of Geotechnical Engineering

Research Area 1 – Geotechnical earthquake engineering

1) The pulsed slippage mechanism, regional distribution characteristics and risk assessment techniques of seismic landslides are proposed.

Application of seismic landslide risk assessment technique along Sichuan-Tibet Railway

2) The discontinuous deformation program for seismic landslide simulation is developed.

The Improvement of DDA Program (IJRMMS)

Accurate Calculation of Landslide Impact and Dynamic & Static DDA Simulations of Daguangbao Landslide (C&G, ENGEO)

3) We have developed an earthquake warning system for China's high-speed railway, making it one of the first batch of high-speed railway earthquake warning system approved to come into service, which contributes to the improvement of the technological level of earthquake prevention and disaster mitigation of high-speed railway and military nuclear facilities in southwest China.

P wave-based schematic diagram of earthquake warning Seismic records and P wave identification results of Chengguan Line Chongyi Station

Research Area 2–Slope engineering

Three dimensional points safety factor analysis of slope based on fine geological modeling

By using computer technology, in the three-dimensional environment, tools such as spatial information management, geological interpretation, geological statistics, stability analysis, deformation trend prediction and graphic visualization of slope geological body all play an important part to establish a fine solid model of slope body for efficient slope analysis. Based on the stress field analysis, the point safety factor of local slope slip is defined as follows:

Safety factor field of multilayer complex slope points Safety factor field of integral sliding points of 3d slope

Research Area 3 – Special geomechanics in mountainous area

1. Research on dynamic characteristics of soft soil under the subway vibration load based on BP neural network

In view of the dynamic characteristics of soft soil under the subway vibration load, the BP neural network model is introduced to get a more accurate simulation of the influence of subway vibration load on the soil mass under complicated circumstances, so as to prove that the BP neural network can be used to calculate the dynamic characteristics of more complex models in the future, and it makes up for the shortcomings of empirical formulas that can only predict the dynamic performance of the simple models.

BP neural network structure The results of BP neural network prediction compared with the experimental data

2.Non-coaxial - anisotropic yield criterion coupled with constitutive relation theory

Based on the traditional Moorcoulomb model, a constitutive model with non-coaxial anisotropy is proposed for the study of general clay and sand soil, and the single shear experiment is used to test the effectiveness of the model. This model is very adaptive and can be used to simulate the bearing capacity of strip foundation and ground settlement of shallow buried tunnel excavation.

Anisotropic yield criterion Application of non-coaxial - anisotropic yield criterion coupled with constitutive relation to tunnel excavation

3. Analysis and evaluation method of 3d reinforced soil structural stability

In view of the deficiency that the existing stability analysis of reinforced soil can only be used in plane strain, a limit analysis method which can fully analyze the three-dimensional damage of the structure is established and a method to evaluate the three-dimensional reinforced soil structure project is put forward, which addresses the problem for engineers who find it difficult to carry out the three-dimensional dam slope stability evaluation.

Three-dimensional failure surface of reinforced soil structure Stability diagram (look-up table method)

Research Area 4 – Deep foundation and foundation treatment

(1) Key technologies for bearing capacity and settlement characteristics of ultra-deep foundation of extra-large bridges

Learning from the national major engineering constructions, we have carried out theoretical research of the foundation theory, bearing capacity of long piles, and pile group deformation theory of railway bridges and other engineering structures under the conditions of high speed, heavy load and significant speed acceleration of existing lines. The innovative design theory of pile foundation bearing capacity of large bridges in unfavorable geological areas has been put forward and remarkable economic and social benefits have been achieved.

2) Large-diameter steel pipe composite pile foundation project for the main part of the Hong Kong-Zhuhai-Macao Bridge

Based on the construction of the Hong Kong-Zhuhai-Macao Bridge, a major national project, a special study is carried out on the testing of large-diameter steel pipe composite pile foundation to help the bridge firmly take root on the seabed.

3) Design theory and key technology of super-deep large caisson foundation in super-thick sedimentary soil of newly-built Shanghai-Nantong Railway Yangtze River Bridge

The new Shanghai-Nantong Railway Yangtze River Bridge has the largest and deepest caisson foundation of its type in the world. Based on the project, the research on the design theory and key technology of the foundation of the large open caisson in the super-thick sedimentary soil is significant for the perfection of the design calculation theory, the optimization of the construction technology and the expansion of theory application.