Integrated approaches for predicting soil-water characteristic curve and resilient modulus of compacted fine-grained subgrade soils

Han, Zhong; Vanapalli, Sai K.; Zou, Wenming

doi:10.1139/cgj-2016-0349

Cited by 37 publications

(13 citation statements)

References 74 publications

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“…where c and d are parameters; for HLJ soil, θ r � 36.56%, q � 1.28, c � 396.31, and d � -565.72; for AK soil, θ r � 42.66%, q � 0.83, c � 24.65, and d � 24.39. Figure 11 shows the three-dimensional fitting results using equation (12) for the two kinds of expansive soil. It can be seen that the initial dry density, matric suction, and volumetric water content all affect each other, and the test points are all near the fitting model surface, indicating that the Gardner model has a good fitting effect.…”

Section: Model Fitting Of Swcc Considering the Initial Dry Densitymentioning

confidence: 99%

“…At present, in addition to the research on deformation and strength [6,7] and solidification improvement [8][9][10] of expansive soil, some achievements have been made in the aspect of the soil-water characteristics [11,12]. Ito and Azam [13] pointed out the swell-shrink path is S-shaped and indicated that it is more accurate to express SWCC by gravimetric water content than by saturation.…”

Section: Introductionmentioning

confidence: 99%

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Study on Soil‐Water Characteristics of Expansive Soil under the Dry‐Wet Cycle and Freeze‐Thaw Cycle considering Volumetric Strain

Niu

Zhang

Zhao³

et al. 2021

Advances in Civil Engineering

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This paper targets the expansive soils in Heilongjiang and Ankang to explore the influence of initial dry density, dry-wet cycle, and freeze-thaw cycle on the soil-water characteristics. The centrifuge method was used to obtain the soil-water characteristic curves (SWCCs) with different conditions. The volumetric strain of SWCC was modified based on the shrinkage test, and the corresponding fitting equations considering different factors were established. The results show that the volumetric water content is modified to consider the volume shrinkage effect of expansive soil, and the modification is more obvious in the high matric suction range. The smaller the initial dry density is, the worse the water-holding capacity of the sample is, and the smaller the air intake value is. The greater the time of the dry-wet cycle is, the greater the saturated volumetric water content of the sample is, and the corresponding water-holding capacity is significantly reduced. When the dry-wet cycle increases to a certain extent, the structure becomes stable. With the increase of the freeze-thaw cycle, the saturated volumetric water content first decreases and then increases. Similarly, after several times of the freeze-thaw cycle, the structure is basically stable. The fitted Gardner model equations under different conditions were proved to be able to describe the SWCCs of the two targeted expansive soils.

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Section: Model Fitting Of Swcc Considering the Initial Dry Densitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Soil‐Water Characteristics of Expansive Soil under the Dry‐Wet Cycle and Freeze‐Thaw Cycle considering Volumetric Strain

Niu

Zhang

Zhao³

et al. 2021

Advances in Civil Engineering

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show abstract

“…A hybrid approach was therefore adopted with one parameter determined via a pedotransfer function (n) and one parameter (α) fitted against a single experimental data point. This method falls in the class of one-point methods widely used in literature (Rajkai et al 2004;Chin et al 2010;Han et al 2017;Yin and Vanapalli 2018). The water retention data point was measured in field after a period of 3 days of no rain, which is quite uncommon at Rest and Be Thankful, to measure the highest suction and, hence, the widest suction range as possible.…”

Section: Water Retention Functionsmentioning

confidence: 99%

Preliminary analysis on the impacts of the rhizosphere on occurrence of rainfall-induced shallow landslides

2019

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Rainfall-induced diffuse shallow landslides are one of the most critical natural hazards as they often evolve into highly destructive flow slides and debris flows. Vegetation is recognised to play a key role in landslide occurrence and is frequently invoked as a potential remedial measure for slope stabilisation at the catchment scale. The beneficial action of vegetation is generally associated with mechanical (root anchoring) and hydrological (suction generated by root water uptake) effects. There is indeed a third effect that has thus far been little explored. The rhizosphere, the portion of soil directly affected by plant roots, is characterised by hydraulic conductivity higher than the underlying soil horizons. This significantly affects hillslope hydrology by promoting lateral diversion of rainwater. This paper presents a case study in Scotland where the rhizosphere is demonstrated to play a major role in controlling shallow landslides. Field investigation and laboratory testing were carried out to characterise the hydraulic conductivity of the rhizosphere and deeper horizons. In turn, this formed the basis for the development of a physically based model for the slope. The model was first validated against its capability to simulate failure of two historical landslides and then exploited to demonstrate the beneficial effect of the rhizosphere. The lesson learned from this study is that shallow landslide hazard can be mitigated by enhancing the capacity of the rhizosphere to act as a natural lateral drainage. This implies that plants with root-system architecture that enhances lateral subsurface flow should be privileged when designing vegetation-based remedial measures.

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“…Alabi [12] and De Barros and Luco [13] calculated the vertical stress of subgrade under the action of vehicle load while studying the impact depth of vehicle load, showing that the vehicle load gradually decreases as the depth increases. Tang [14] and Han et al [15] studied the mechanical behaviour of the dynamic load of subgrade soil and the response characteristic of dynamic stress while analyzing the law governing the impact on the dynamic stress of subgrade exerted by the value of dynamic vehicle load, frequency of dynamic load, different depths of subgrade, and number of dynamic load actions. It was also proved that the dynamic stress varies among different depths within the subgrade work area and gradually decreases as the depth increases [16].…”

Section: Introductionmentioning

confidence: 99%

Calculation and Control Methods for Equivalent Resilient Modulus of Subgrade Based on Nonuniform Distribution of Stress

Yao

Qian

et al. 2019

Advances in Civil Engineering

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The resilient modulus of subgrade is a design parameter of the pavement structure, which is significantly affected by the overlying load and traffic load. It is important to calculate the equivalent resilient modulus of the top surface of subgrade based on the nonuniform distribution of resilient modulus in subgrade. This paper takes the fully weathered granite soil as the research object. Firstly, the soil density of different layers of the subgrade structure is calculated by the degree of compaction of different subgrade layers. Secondly, the overlying load of each point in the subgrade is determined based on the quality of subgrade. Thirdly, the subprogram of the finite element software is compiled and redeveloped based on the elastic constitutive model, and the calculation method for the resilient modulus of each point in the subgrade under the traffic load is proposed when the convergence criterion is set up. Finally, according to the deflection equivalence of the elastic double layer and elastic half-space, the calculation and control methods for equivalent resilient modulus of the top surface of subgrade under nonuniform stress distribution are put forward, and the field verification tests are carried out. The results show that the error range between numerical calculation and field measurement of equivalent resilient modulus of subgrade is 10%. It shows that the calculation method for equivalent resilient modulus of subgrade proposed in this study is reasonable and effective. The equivalent resilient modulus of subgrade decreases with the increase of traffic load. And the resilient modulus of subgrade soil increases with the increase of subgrade depth. The resilient modulus of subgrade soil has a significant impact on the equivalent resilient modulus of subgrade after the overlaying gravel layer. The equivalent resilient modulus of the subgrade with the gravel layer increases with the increase of the resilient modulus of the subgrade soil.

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Integrated approaches for predicting soil-water characteristic curve and resilient modulus of compacted fine-grained subgrade soils

Cited by 37 publications

References 74 publications

Study on Soil‐Water Characteristics of Expansive Soil under the Dry‐Wet Cycle and Freeze‐Thaw Cycle considering Volumetric Strain

Study on Soil‐Water Characteristics of Expansive Soil under the Dry‐Wet Cycle and Freeze‐Thaw Cycle considering Volumetric Strain

Preliminary analysis on the impacts of the rhizosphere on occurrence of rainfall-induced shallow landslides

Calculation and Control Methods for Equivalent Resilient Modulus of Subgrade Based on Nonuniform Distribution of Stress

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