01

Highway foundation treatment techniques in permafrost regions of the Qinghai-Tibet Plateau: Current practices and future trends

Bo Tian

Abstract：In the context of global warming, existing highways in the permafrost regions of the Qinghai-Tibet Plateau are facing multiple challenges, including surface settlement, roadside water accumulation, groundwater saturation, thickening of melting interlayers, and continuous permafrost degradation. These issues pose serious obstacles to the remediation and rehabilitation of existing highway subgrades in the region. This paper reviews the evolution of foundation design methods in permafrost regions abroad and traces the development of highway subgrade design approaches specific to permafrost areas in China. Based on the latest field investigation data, the causes of subgrade settlement along existing highways in the Qinghai-Tibet Plateau are analyzed, and areas for improvement within the current design system are identified. The study proposes the advancement of a third design principle-“proactively improving foundation conditions”, to complement the existing principles of “protecting permafrost” and “allowing permafrost thawing”. It introduces the concept of “treating permafrost foundations” and presents a collaborative design methodology for the pavement-subgrade-foundation system in permafrost regions. This integrated approach enables a more nuanced analysis of how climate-induced changes in foundation characteristics influence subgrade deformation and structural stability. Furthermore, this paper categorizes and discusses the types, characteristics, engineering applications, and performance of existing subgrade treatment techniques, including shallow foundation (0-3 m) and deep foundation (>3 m) treatments. It highlights urgent technical challenges that need to be addressed, such as conducting more refined hydrological and geological investigations, improving the engineering geological evaluation index system, establishing long-term performance assessment methods for permafrost treatment techniques, and developing new treatment materials and equipment for treatment. This research aims to provide scientific support for the effective management and rehabilitation of highway subgrade subsidence in the permafrost regions of the Qinghai-Tibet Plateau.

02

Calculation method of spatial effect and safety factor of V-shaped gully embankment

Yun Que, Jisong Zhang, Xiaohui Zhu, Zhihang Wang

Abstract：V-shaped gully embankment presents unique spatial effect due to special terrain. To study the impact of terrain factors, to shore side Angle, groove width, high embankment fill, trailing edge slope and frontal slope factor as control variable, and gray relevance principle on the basis of the principle of strength reduction method, the spatial effect mechanism, influence factors and the correlation degree, three-dimensional slope safety factor calculation method and the effects of space conditions are analyzed. The results show that the deformation of embankment is constrained by the side bank of the gully, and the uneven displacement occurs, which leads to the deflection of the stress transfer inside the embankment, and the partial earth pressure is transferred to the side bank, and the soil arch phenomenon occurs inside the embankment. The four factors influencing the spatial effect of embankment are side bank Angle, ditch bottom width, embankment filling height and frontal slope factor. At the same time, based on the spatial effect coefficient curve, the calculation method of three-dimensional embankment stability coefficient and the necessary and sufficient conditions for spatial effect are proposed. By comparing the results of the three-dimensional stability coefficient calculation method established in this paper with the traditional strength reduction method under different conditions, it is found that the spatial effect coefficient is only related to the four topographic factors such as the width of the ditch bottom, and has nothing to do with the mechanical parameters or constitutive model of the embankment fill and bedrock. Finally, the accuracy is verified by engineering cases, which can provide reference for the calculation of similar embankment stability coefficient.

03

Model testing and mechanical analysis of frictional resistance in rock pipe jacking through water-rich fractured strata

Chao Zhang, Tianxiang Sun^2,3, Shichu Li, Jiacheng Li^2,3, Zifan Song^2,3, Xiangfeng Lü^2,3

Abstract：Rock pipe jacking in water-rich fractured strata presents considerable construction challenges due to significant disturbance of the surrounding rock. However, the variation in rock mechanical properties and frictional resistance prediction remains inadequately studied. This study employs a combined approach of model testing, theoretical analysis, and engineering practice to investigate the variation patterns of surrounding rock pressure and displacement across different rock classes influenced by groundwater. A simplified mechanical model is proposed to represent the pipe–slurry–residue contact frictional resistance, and its validity is analyzed using model test results and engineering measurements. The findings indicate the following. (1) The lower surrounding rock classes experience more pronounced displacement variations and stress release, with groundwater further amplifying these effects. (2) The unit frictional resistance increases linearly with the groundwater correction factor, distance from the groundwater level to the pipe, and friction angle between the pipe and residue zone, while it decreases with the elastic modulus, following a power function relationship. (3) The theoretical and model test values show consistent trends in frictional resistance variation, with an average error of 9.42% in unit frictional resistance, indicating strong agreement. These findings validate the applicability of the proposed model and provide a reliable prediction range for engineering conditions. The outcomes offer a theoretical foundation and practical data for frictional resistance prediction and construction optimization in rock pipe jacking projects within water-rich fractured strata.

04

Modifying performance of bridge deck concrete compositing graphene oxide/steel fibre

Chunmei Liu, Xinghao Xi, Zhongyue Chao, Futao Chen, Tianyi Su

Abstract：To enhance the mechanical properties and durability of bridge deck concrete, this paper uses graphene oxide to modify steel fibre-reinforced concrete. By selecting different graphene oxide pre-treatment methods and doses, compressive strength, flexural strength, chloride ion permeability and frost resistance tests are performed to investigate the influence of graphene oxide pre-treatment methods and doses on the properties of steel fiber reinforced concrete. The results showed that ultrasonic pretreatment of graphene oxide was better than mechanical mixing treatment on the performance of steel fibre. The strength development of both rise and then fall with the increase in dosage, and the optimal dosage was 0.075%. At this time, the compressive strength of the ultrasonic treatment group at 7 d and 28 d were 46.33 MPa and 64.58 MPa, respectively, and the flexural strength was 6.36 MPa and 8.13 MPa, respectively. The depth of penetration of the chloride ions is 3.87 mm and the rate of loss of mass after 300 freeze-thaw cycles is only 6.33%. Extensive research has shown that adding graphene oxide to fibre-reinforced concrete greatly improves its mechanical and durability properties, prolonging bridge deck concrete's service life.

05

Bridge deck disease detection and screening method based on point cloud Gaussian curvature field

Liang Tang, Xiangyu Zhang, Tong Wu, Yijun Liu, Xinyu Li

Abstract：In order to efficiently and automatically detect and classify bridge deck diseases, a method using Gaussian curvature to detect bridge deck surface diseases is proposed. When there is a defect in the bridge paving surface, there is a high-order discontinuity in the common boundary between the defect area and the non-defect area, that is, the surface Gaussian curvature value at the common boundary is a discontinuous change. According to the location and extent of Gaussian curvature mutation, the disease was located and quantified, and the disease was classified and screened by the Gaussian curvature value distribution feature and Hu rectangular morphological feature. For a 3D point cloud model of a concrete continuous girder bridge, the distribution of Gaussian curvature values in the paved area of the bridge deck was analyzed. The results show that the distribution of Gaussian curvature can characterize surface diseases such as pavement pits and loose spalling of the bridge, and this method is consistent with the assessment results of disease degree by traditional detection methods, and has high implementability, which provides a new technical approach for bridge deck disease assessment.

06

Thickness of heat insulation layer of electric heating snow and ice melting pavements

Duanjun Han^1,2, Can Li, Jiayuan Xiong, Xiaoqing Wei, Hui Zheng

Abstract：In order to study the influence of thermal insulation layer thickness and carbon fiber heating wire temperature on the snow and ice melting of the pavement under pavement daily cycle thermal boundary conditions, the heat conduction equation of the conventional asphalt pavement structure is built when the heating wire is laid horizontally, and the numerical solution of the temperature field is obtained by solving the partial differential equation using MATLAB PDE toolbox. The example chooses the freezing meteorological conditions on a certain winter day in Hunan Province, the temperature of the constrained pavement is above 4.8 ℃, and the temperature of the heating wire is 30-50 ℃. The temperature rise rates of the pavement are calculated when the thickness range of the thermal insulation layer is 5-40 mm. Results showed that in the hot summer and cold winter areas represented by Hunan Province, the average temperature rise rate of road surface with a thermal insulation layer thickness of 5mm is about 3.5-9 times higher than that without thermal insulation layer; while that with a thermal insulation layer thickness of 10 mm is increased by 3.55-9.5 times. After the thickness of the thermal insulation layer exceeds 10 mm, the increase trend of the average temperature rise rate of road surface is not obvious. At the same time, the temperature rise rate of the road surface is not only nonlinear with the thickness of the thermal insulation layer but also nonlinear with the temperature of the heating wire. Therefore, it is not that the thicker the thermal insulation layer, the better the temperature rise and defrosting effect of the road surface. In addition, the additional heat insulation layer prevents most of the heat generated by the heating wire from flowing underground, so that the temperature distribution of the road surface is more uniform. The pavement temperatures with insulation are also higher than those without insulation. The simulation results for the cold and harsh places reveal that the heating wire temperature should be increased to 50-70 ℃ when the limited road temperature is likewise over 4.8 ℃, and the effect of insulation layer thickness is still consistent with the example. Theoretically, considering the road surface heating performance and the engineering costs, it is considered that the hot wire temperature of 30-70 ℃ and the thermal insulation layer of 5-10 mm are more suitable. The conclusions are also applicable to cold and severe regions and can provide a reference for choosing the optimum economical thickness of the insulation layer when the heating wire assists the deicing or snow-melting on the road surface with the periodic thermal boundary condition.

07

Performance evaluation and optimization design of steel slag-rubber asphalt mixture

Jianmin Wu, Shaoqing Li, Changchun Xu

Abstract：Steel slag and wasted rubber tire are both solid wastes which are high production and difficult to dispose. Steel slag-rubber asphalt mixture (SSRAM) was prepared by using steel slag which replaced part of coarse aggregate and rubber asphalt. In order to study the regularity of gradation, steel slag content and binder property on the road performance of SSRAM, three kinds of coarse aggregate fractal dimension values (D) and two kinds of fine aggregate fractal dimension values (D) were selected according to fractal theory. The performance of SSRAM in three-level orthogonal scheme with three factors (D steel slag content and rubber content) was analyzed and the performance of the mixture under two kinds of D was compared. The results show: In the selected levels, Dc is the main factor affecting the high temperature stability and anti-freezing and thawing performance of SSRAM. With the decrease of D, aggregate gradation becomes coarser the dynamic stability of the mixture increases and the predicted permanent deformation decreases, but the anti-freezing and thawing performance decreases; the content of steel slag is the main factor affecting the optimal asphalt-aggregate ratio and low temperature bending strain of SSRAM. With the increase of steel slag content, the optimal asphalt-aggregate ratio increases and the low temperature bending strain of the mixture also increases; compared with base asphalt, rubber asphalt shows better performance, but the rubber content has little effect on the performance of the mixture. All SSRAM with different composition have good volume stability. For the better road performance, SSRAM composition with D=2.1, D=2.55, steel slag content 60% and rubber content 21% is recommended.

08

A communication channel allocation approach considering competition at the intersection

Yining Ren, Zhizhou Wu, Yunyi Liang, Tianjun Yang

Abstract：This study investigates the problem of V2R (Vehicle to Road Side Units,V2R) communication channel allocation at an intersection considering communication channel competition among each vehicles. This problem is formulated as a mixed-integer nonlinear program with equilibrium constraints. The object of this problem to minimize V2R communication delays of the whole system by optimizing the number of connected autonomous vehicles (CAVs) communicating with each RSU (Road Side Units, RSU). Complementary constraints based on User Equilibrium is introduced to guarantee each CAV can connect with RSU with their least delay in the competition. A piecewise linearization method is introduced to linearize and help solve the model. In the numerical experiment, the proposed model is compared with the models following System Optimum principle. By comparison, the results show that the proposed model can better achieve the balance between the benefits of the whole V2R system and each CAV individuals. The finding of this study can be applied to the situation where communication channel is crowded at the intersection.

Journal Introduction

HTRD

The Journal of Highway and Transportation Research and Development (English Edition) (HTRD) was established in 2006 as a leading academic journal under the sponsor of the Research Institute of Highway, Ministry of Transport, published quarterly by the Journal of Highway and Transportation Research and Development Co., Ltd. As of 2024, the journal is co-published by Tsinghua University Press and has transitioned to an Open Access Journal. Articles co-published between 2006 and 2023 are available for access at https://ascelibrary.org/journal/jhtrcq.

HTRD is an international Englishscientific journal. HTRD’s topics include civil engineering (road, bridge,tunnel), traffic engineering, intelligent transportation, environmental engineering, transport economics, automotive engineering, logistics engineering, disaster prevention, etc.

Sponsor: Research Institute of Highway, Ministry of Transport.

Co-publisher: Tsinghua University Press (2024-).

American Society of Civil Engineers (ASCE) Library (2012-2023).

Indexed: DOAJ, ProQuest, INSPEC, Ulrich, CA, AJ VINITI, WJCI, COPE.

期刊官網(wǎng)：

https://www.sciopen.com/journal/2095-6215

投稿網(wǎng)址：

https://mc03.manuscriptcentral.com/htrd

公路交通科技

中文刊：https://www.gljtkj.com/CN/home

英文刊：https://www.sciopen.com/journal/2095-6215

來(lái)源：雜志社

編發(fā)：辦公室

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