It is imperative to construct high-level, innovative and challenging courses in the teaching of colleges and universities. It is also of great significance to explore innovative teaching methods for improving students’ learning effect. In this paper, the course “Civil Engineering Construction” of a civil engineering major is taken as a reform example. In this teaching-innovation mode, guided by students’ moral education and students’ achievements, and the course platform is built in order to achieve the education concept of sustainable development and cultivate applied talents who can solve complex problems in civil engineering. In teaching practice, “Dual Platforms”, which combines course teaching platform and virtual simulation platform, is built mainly to expand the learning approaches. The “Three Educations” mode, which combines on-site education, classroom education, and mental health education, is established to improve the comprehensive quality of students. Comprehensive academic evaluation is carried out through “Four Reports”, including an open assignment report, special technical study report, BIM (building information modeling) technical work report, and final comprehensive written test report. Through studying this course, students not only master the knowledge of civil engineering construction, but also acquire knowledge-innovation ability, such as thesis publication, patent writing, discipline competition, and cultivating the craftsman spirit and social responsibility to abide by professional ethics in future work. This teaching innovation mode has been implemented for 12 years and achieved excellent results in cultivating students’ intelligent ability for sustainable development. It has been promoted in 14 courses, and has certain reference significance for engineering-course teaching.

Here we study the effects of nano clay and polypropylene fiber on the unconfined compression and splitting properties of lime soil. Through a series of unconfined compressive strength (UCS) tests and splitting strength (STS) tests, the mechanical properties of lime soil (LS), nano clay modified lime soil (NLS), fiber modified lime soil (FLS), nano clay and fiber composite modified lime soil (NFLS) are analyzed, and the volume calculation formula of each phase in NFLS is deduced. Nano clay content α_n, porosity volume η and lime volume L_Vi as independent variables, and the prediction models of UCS and STS of NFLS were established. Furthermore, the microstructure of LS, NLS, FLS and NFLS was analyzed by scanning electron microscope (SEM). It can be concluded that (1) with the increase in nano clay content, the UCS and STS of LS and FLS gradually increase. With the increase in fiber content, the UCS of LS first increases and then decreases, while the UCS and STS of NLS and STS of LS increase with the increase in fiber content, and the optimal fiber content is 0.75%. (2) UCS and STS of NFLS and η/L_Vi meet the linear relationship. The empirical formulas of UCS and STS established in this paper have a prediction accuracy of less than 10%. The strength of NFLS can be predicted according to the dry density of the sample and the content of each component material. (3) Nano clay can fill the pores of LS and promote the pozzolanic reaction between lime and soil, while fiber mainly plays a reinforcing role in LS, so as to improve the UCS and STS of LS. In NFLS, nano clay can improve the interfacial properties between fiber and LS, so as to improve its UCS and STS. This study can provide a reference for the modification technology of lime soil.

In order to explore the modification effect of carbonization time on nano-MgO-modified cement soil, unconfined compressive strength tests of nano-MgO-modified cement soil with carbonization times of 0 h, 6 h, 1 d, 2 d and 4 d were carried out. A method for normalizing the stress–strain curve was proposed, and the influence of nano-MgO content and carbonization time was investigated from the three aspects of compressive strength, peak strain and energy dissipation. The test results show the following: (1) The compressive strength of the modified cement soil can be significantly improved by adding 1.0% nano-MgO and after 1 d carbonization. (2) Under the same nano-MgO content, the peak strain of the modified cement soil after 2 d carbonization reaches the maximum, which can significantly increase its ductility. However, the nano-MgO content has little influence on the peak strain of the modified cement soil. (3) Under the same nano-MgO content, the energy dissipation rate of the modified cement soil after 1 d carbonization reaches the maximum, which can better resist the damage of external load.

The amount of boron waste increases year by year. There is an urgent demand to manage it in order to reduce the environmental impact. In this paper, boron waste was reused as an additive in road base material. Lime and cement were employed to stabilize the waste mixture. Mechanical performances of stabilized mixture were evaluated by experimental methods. A compaction test, an unconfined compressive test, an indirect tensile test, a modulus test, a drying shrinkage test, and a frost resistance test were carried out. Results indicated that mechanical strengths of lime-stabilized boron waste mixture (LSB) satisfy the requirements of road base when lime content is greater than 8%. LSB can only be applied in non-frozen regions as a result of its poor frost resistance. The lime–cement-stabilized mixture can be used in frozen regions when lime and cement contents are 8% and 5%, respectively. Aggregate reduces the drying shrinkage coefficient effectively. Thus, aggregate is suggested for mixture stabilization properly. This work provides a proposal for the management of boron waste.

Resource utilization of iron tailings powder is an effective measure to reduce the dam-break risk of an iron tailings reservoir. Adding polypropylene fiber to iron tailings powder can improve its shear performance. Direct shear tests were carried out on reinforced iron tailings powder with polypropylene fiber with dosages of 0%, 0.25%, 0.5%, 0.75%, and 1%, respectively. The normal stresses during the tests were 100, 200, 300, and 400 kPa, respectively. The test results show that with the increase of polypropylene fiber dosage, the cohesive force of iron tailings powder firstly increases and then decreases gradually, and the internal friction angle firstly decreases and then increases. The back propagation (BP)neural network was used to fit the shear force (F) and shear displacement (s) of the test to obtain the F-s function relationship that satisfies the accuracy. Based on the energy dissipation theory, the direct shear energy dissipation of polypropylene-fiber-reinforced iron tailings powder was calculated. The mathematical model of energy dissipation of fiber interfacial failure was derived by the fiber distribution model. The interfacial strength parameters of polypropylene fiber were calculated based on the direct shear test data and the mathematical model of fiber interfacial energy dissipation. The test results show that the addition of polypropylene fiber from the perspective of energy dissipation can improve the shear properties of iron tailings powder.