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Li Feng

Bio: Li Feng is an academic researcher from Changsha University of Science and Technology. The author has contributed to research in topics: Subgrade & Moisture. The author has an hindex of 5, co-authored 11 publications receiving 156 citations.

Papers
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Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper analyzed the physical and chemical properties of construction and demolition wastes (CDW) subgrade construction case in Beijing, and a series of tests (compaction degree test, settlement observation, Portable Falling Weight Deflectometer test) were carried out.

123 citations

Journal ArticleDOI
TL;DR: In this paper, the authors developed an efficient and accurate methodology to estimate the resilient modulus of subgrade soils using a model incorporating stress dependence and a new resilience modulus model.
Abstract: This study aims at developing an efficient and accurate methodology to estimate the resilient modulus of subgrade soils. First, a new resilient modulus model incorporating stress dependence and moi...

62 citations

Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper determined the moisture contents of unsaturated clay embankments in southern China considering the stress state, and 6 frequency domain reflectometry sensors were installed in a widened embankment to monitor the moisture content.
Abstract: To determine the moisture contents of unsaturated clay embankments in southern China considering the stress state, 753 moisture data of three existing embankments for about 20 years were measured, and six frequency domain reflectometry sensors were installed in a widened embankment in southern China to monitor the moisture content. The soil water characteristic curve (SWCC) and stress-dependent soil water characteristic curves (SDSWCCs) were determined in the laboratory using a pressure plate apparatus and a stress-dependent parametric equation was established. The finite element model of a typical unsaturated clay embankment in southern China considering the SWCC and SDSWCCs was created. Then, the variation of the moisture contents of the clay embankment was simulated. The results show that the vertical stress has an obvious effect on the moisture distribution in embankments, especially the positions inside embankments where the vertical stress is large and cannot be neglected. The finite element model considering the SDSWCCs, therefore, should be selected when analyzing the moisture filed of embankments in southern China. For the existing clay embankments in southern China, their moisture contents gradually increase from the optimum moisture content to equilibrium values, which is close to the plastic limit and increases by 99% of the optimum moisture content. In addition, the resilient modulus values at different locations of the embankment and that of the whole embankment are reduced by 55 to 62%. And the safety factor of the slope obviously decreases, and its reduction is greater than 60%.

36 citations

Journal ArticleDOI
TL;DR: According to the Gray correlation analysis results, the permanent deformation of highway subgrade filled with C&D materials is influenced by the deviator stress most significantly, followed by moisture content, degree of compaction, and confining pressure.
Abstract: Construction and demolition (C&D) materials obtained from the demolition of buildings are proven to be qualified and sustainable subgrade fillers. The permanent deformation response of subgrade C&D materials under different moisture contents, degrees of compaction, deviator stresses, and confining pressures was revealed by carrying out dynamic triaxial texts. Then, using a four-factor and three-level orthogonal test and by calculating the Gray correlation degree of each factor, the influence degree of each factor on the permanent deformation was determined. The results indicated that two different response types of the permanent deformation of subgrade C&D materials, plastic shakedown and plastic creep, were identified as reason behind the increase in stress levels. Also, according to the Gray correlation analysis results, the permanent deformation of highway subgrade filled with C&D materials is influenced by the deviator stress most significantly, followed by moisture content, degree of compaction, and confining pressure. Finally, a permanent deformation prediction model about this kind of subgrade filler with a reasonable prediction accuracy was proposed.

26 citations

Journal ArticleDOI
TL;DR: In this paper, a finite element model of sand cushion and cover considering different materials and thicknesses for a typical embankment was built, and 20 numerical analyses of transient seepage in the embankments were simulated.
Abstract: To achieve durability of the embankment in southern China, a method to control the change of moisture content with the cushion and cover was proposed. A finite element model of cushion and cover considering different materials and thicknesses for a typical embankment was built, and 20 numerical analyses of transient seepage in the embankment were simulated. The results show that the sand cushion effectively blocks the effect of groundwater capillary rise and the minimum thickness of the sand cushion is 75 cm without considering the atmospheric environment. With the combination of sand cushion and clay cover, as the thickness of the clay cover increases, the duration time of the moisture content from the initial to relative equilibrium state increases, but the equilibrium moisture content is the same as that of the original embankment. Besides, with the combination of the sand cushion and sand cover, the moisture content inside the embankment remains the same, which is consistent with the optimum moisture content during construction. The combination of 75 cm sand cushion and 30 cm sand cover is a very effective method to block groundwater and atmospheric environment, and achieve the control of the humidity stability of the embankment in southern China.

10 citations


Cited by
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Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper analyzed the physical and chemical properties of construction and demolition wastes (CDW) subgrade construction case in Beijing, and a series of tests (compaction degree test, settlement observation, Portable Falling Weight Deflectometer test) were carried out.

123 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a comprehensive review on the workability and mechanical properties of fiber reinforced recycled aggregate concrete (FRAC) and highlight the most promising and feasible strength enhancement methods for the FRAC mainly using steel fiber, polypropylene fiber (PPF), basalt fiber (BF), and glass fiber (GF).

83 citations

Journal ArticleDOI
01 Aug 2021-Catena
TL;DR: In this article, the micro-scale structural characteristics of the loess exposed to acetic acid, phosphoric acid, sodium hydroxide, and sodium sulfate respectively are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy tests.
Abstract: Soil contamination not only can cause environmental problems but also lead to a notable change in the mechanical properties of soil. Loess widely distributed over North-West (NW) China is featured with the metastable structure, and chemical contaminants produced especially during the rapid development of NW China in recent years seriously threaten the fragile loess environments. When exposed to chemical contaminants, the impacts on the microstructural characteristics of the loess and the resultant mechanical properties are deemed critical for land reclamation in NW China. In light of this, the microscale structural characteristics of the loess exposed to acetic acid, phosphoric acid, sodium hydroxide, and sodium sulfate respectively are studied using scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy tests. Additionally, their resultant macroscale mechanical properties are determined by direct shear tests. The deterioration mechanism regarding the microscale structural characteristics when exposed to the contaminants is revealed, and the resultant macroscale mechanical properties present a good correspondence with the deteriorated microscale structural characteristics. The findings of this work provide some guideposts for contaminated land reclamation in NW China.

74 citations

Journal ArticleDOI
TL;DR: In this article, a rubber-modified RAC (RRAC) notched beam specimens with three recycled aggregate substitutions (0, 50, and 100%), and four rubber contents (0., 2, 4, and 6) were tested using the three-point bending test.

67 citations

Journal ArticleDOI
TL;DR: In this paper, a systematic review of scientific publications on zero emission neighbourhoods, positive energy districts and similar concepts of climate friendly neighbourhoods (CFN) is presented, where the aim is to identify focus areas, research gaps and future research possibilities.

59 citations