High-grade Highways Research Articles

Study on Factors for Determination of Highway Subgrade Height

With increasing concentration on highway land issue as the new round of highway construction, reducing land occupation and earthwork volume of highway engineering is necessary under the historical background of building “resource-saving and environment-friendly” society. It’s been widely known now in the industry that subgrade height of highway in China, especially high-grade highways, is on the high side. Therefore, it’s significantly necessary to discuss and study on appropriate subgrade height. This paper explains advantages and disadvantages of low-filled embankment and expounds current situation of indexes for subgrade performance – moisture, modulus resilience and permanent deformation; it proposes basic thinking of determining subgrade height mainly through meeting subgrade performance and engineering requirements and realization approach of the method.

Method of Determining the Length of Approach Slab for Highway Bridge

Approach slab is mainly used to slowdown or reduce uneven settlement of bridge heads as far as possible. Setting approach slab at back of bridges and culverts is an effective and necessary way to avoid faulting slab ends between abutment and road in high-grade highway. It has come into general application and achieved good results. But nowadays, approach slab is designed based on previous experience or being set a size parameter directly instead of being made a special design. Theory and experience that the design based on is unreasonable. Author confirm the need for setting approach slab and give the reference value about length of approach slab for different grade highway according to analysis and study on the forced state of the moving vehicles at highway-bridge junction with or without approach slab.

The Effect of Asphalt and Aggregate Gradation on the Low-Temperature Performance of Asphalt Mixtures for Intermediate and Underlying Course

Aiming at the asphalt mixture type used in intermediate and underlying course of high-grade highways in Northeast region of China, the research of effect of asphalt and gradation on the low-temperature performance of asphalt mixture was carried out to recommend asphalt grade and grading type which is suitable for intermediate and underlying course of high-grade highway in Northeast region of China. The results show that the asphalt and gradation of aggregate has important impact on the low-temperature performance of asphalt mixture. The low-temperature bending creep rate of Grade A No.90 asphalt mixture specimen prepared is faster than that of Grade A No.70 asphalt mixture. To further illustrate the low-temperature deformation resistance performance of Grade A No.90 asphalt is better than that of Grade A No.70.asphalt.The low-temperature bending creep rate of modified asphalt mixture of gradation GLAC-20 is greatly improved. Grade A No.90 asphalt modified is suggested to use in intermediate course, and the gradation type which is suitable for intermediate and underlying course is recommended for reference.

Effects of Framed Embankment for High-Grade Expressway in Permafrost Regions

Construction of high-grade highways is an important action to meet the requirement of communication and transportation in permafrost regions. Frame embankment is proposed to reduce the scale effects caused by wide pavement. Numerical simulation method is employed to analyze the improvement of frame embankment for thermal stability of roadbed, with the consideration of global warming. Compared the response of permafrost at symmetric position of each embankment to construction, the consistency degree of response is taken as decision fundament. Two indexes are selected, that is, the difference of permafrost table between the embankment and that at natural side, and the change of mean annual geothermal under the embankment. Additionally, the convenient for construction and wind-blown sand hazard are considered to determine reasonable frame space. So, numerical simulation of flow field of wind around embankments is carried out. It is concluded that the minimum space between two embankment is 6 m. The aim of this study is to provide scientific guidelines on construction of major permafrost engineering in the future.

A Study on the Spiral Line Development Applied in the High-Grade Highways Design

The concept of spiral line development (SLD) is introduced at first in this paper, then the design idea of SLD is discussed, and the characteristics and patterns of SLP are summarized. According to the terrain adaptability and linear continuity requirements of SLP, rationality of the SLD applied in the high-grade highways in mountain areas are analyzed from the aspects of technology, safety, economy and environmental protection. The results show that SLD is a better decision in the case of the limitation of topographic and geological conditions, too large height difference between the two control points, no natural line development conditions, and the reverse loop development dissatisfying the requirements of high-grade highways index

Experimental Study on the Rutting Deformation Mechanism of Asphalt Pavement

Asphalt mixture is the common pavement materials in high-grade highway. The rutting is one of the main failure modes. Temperature and loading are the two main factors cause rutting of pavement.The rutting experiment were carried under same loading in different temperatures and in same temperature under different loading, the relation curves between rutting deformation and load duration were obtained. Comparing the rutting deformation and dynamic stability, the influence mechanism of temperature and loading to rutting is studied by the experimental method. The research results have theoretical guidance meaning in controling the rutting deformation of pavement materials and prolonging the service life of asphalt pavement.

Influence of Caustic Soda Flakes-Phosphogypsum on Activation and Microstructure of Carbide Slag-Flyash

This article studied the influence of the caustic soda flakes (CSF) phosphogypsum (Ard) activator on the properties and microstructure of hydration product generated by carbide slag (CS)-flyash (FA) system which used in high-grade highways pavement. Studies have shown that: the main hydration products generated by carbide slag-flyash system are calcium silicoaluminate hydrate (C-A-S-H) and ettringite (AFt), but the reaction of hydration is slow and the content of hydration products is low. However, the caustic soda flakes-phosphogypsum can promote the formation of C-A-S-H and AFt, so can improve the strength and engineering application of the system effectively.

Research of Non-Probabilistic Reliability of Soil Structure of High-Grade Highway Based on Interval Analysis

In this paper, through the study on the non-probabilistic based on the interval analysis of soil structure, solves the key theoretical issues of non-probability measure and methods, It is more suitable for evaluation of the roadbed design problems with less experimental data.

Method of TER Location for High-Grade Highway Based on Fuzzy Rough Set

The location technology of Truck Escape Ramp(TER) is the important guarantee for fully developing the TER actions and ensuring operation safety of heavy vehicles on long-steep downgrade. In order to improve the precision of TER location, this paper thoroughly analyzed the influence factors of TER location from the view of traffic accidents statistical data, road conditions and vehicle status. Expounded the theory of fuzzy rough set. Put forward the method of highway TER location based on fuzzy rough set. Used this method to evaluate the running safety of the unit sections on the long-steep downgrade. Calculated the comprehensive safety index values of sample sections and made ones with high comprehensive safety index values as the candidate sections for TER. Determined the accurate positions of the TER based on comparison of the comprehensive safety index value of adjacent candidate sections. Setting effect shows that the TER position determined by the method are scientific and rational.

Strength and Drying Shrinkage of Pavement Concrete with Nano-Particles

With the development of national economy in Mainland China, the heavier vehicles and traffic flow have arisen in highway transportation. Concrete pavement has high strength and good durability, and thus is widely used in high-grade highway. Due to the small dimension, nano- materials have many unique physical and chemical properties, and become the focus of material science field. In this thesis, based on the unique characteristics of nano-materials, the ordinary concrete with nano-SiO2 or nano-TiO2 is prepared to research the drying shrinkage of pavement concrete. The test results indicate that the concrete with nano-SiO2 and nano-TiO2 in the amount of 2.0% and 1.0% by weight of binder have the respectively biggest drying shrinkage rate of the same concrete type, which are significantly increased than the ordinary concrete. After 28 days, the dying shrinkage rate of the concrete with nano-TiO2 is 1.6 times to the ordinary concrete.

The Application Analysis of Micro-Surfacing in High Grade Highway Asphalt Pavement Preventive Maintenance

In domestic asphalt pavement micro-surfacing technology is a new kind of pavement maintenance technology. Starting with the micro-surfacing technology application effect, we analyzed the micro-surfacing technology characteristics and application conditions. We also analyzed and discussed the application prospect, strive to provide a technical reference for promotion and application of micro surfacing technology.

Loess Highway Tunnel Construction Process of Three Dimensional Numerical Simulation

In recent years, as China's national sustained and rapid economic development, the state increased investment to middle-western region, promote the regional development of high grade highway. Therefore, highway tunnel through loess area is getting more and more. Due to the special physical properties of loess, it makes the loess tunnel construction a hot topic. To study on the deformation law of the loess highway tunnel, this paper based on the Shanxi Province Guang Ling to Hun Yuan highway tunnel—East Fu Yao tunnel, we simulate the whole section pre-reinforcement construction technique for three dimensional numerical, and combined with field monitoring measurement to compare and analyze in paper

High-Grade Highway Safety Evaluation Method Based on Grey Clustering

Evaluation for traffic safety is very important to improve traffic safety. First analyzes high grade highway security characteristic, then according to grey characteristics of traffic safety system, proposed high grade highway grey clustering evaluation model, and carries on the model to Henan province high grade highway's safe condition status evaluation, thus confirms this method the validity. The research showed that this model is a effective way which measure high grade highway transportation degree of security.

Analysis of Research Topic on Cement Cold-Recycled Base of High-Grade Highways

This review presents the difference between cement cold-recycled base and cement-stabilized new aggregate base. Old aggregate gradation is obviously beyond the prescribed limits. Due to old cement hydration products, the gradation of old mixture is not real by screening test, just called it “Fake Gradation”. The various factors of influence on pavement performances are introduced, including cement content, gradation, fine aggregates content, old material characteristic and water loss ratio. The main pavement perforamnce, such as mechanical properties, shrinkage properties and fatigue properties of cement cold-recycled mixture may not meet the requirement of high grade highways. The research topic of cement cold-recycled base is pointed out, which includes properties of old materials, the application of additives, the methods of improving pavement perforamnce and the establishment of pavement performances evaluation indexes, etc.

Influence of High-Grade Highway Construction on Industry-Economic Belt in Heilongjiang Province

With the victory of “Three-year decisive battle”of road construction in Heilongjiang Province and the formation of high-grade highway network, high-grade highways gradually have profound effects on promoting economic and social development and enhancing the public life level, as well as meeting the traffic demands in Heilongjiang province. The influence of the highway construction on industrial-economic belt in Heilongjiang province was analyzed. As an example, by forecasting various index of Harbin-Daqing-Qiqihar Industrial Corridor, we confirmed that the construction of high-grade highways in Heilongjiang play positive roles in industrial-economic belt.

Planting Optimization of Glare Avoidance Model on Flat Road

In order to solve the problem of the glare avoidance on flat road, studying the high-grade highways' planting model through field measurements and modeling methods. Based on the flat road model and geometric rules, putting up an anti-'s’ shape planting model. According to the measured data of the City Second Ring Road (Two stage highway) of Jinhua, verifying the feasibility of the model. Depending on the results, a series of suggestions were provided to reduce planting cost, expand the shielding angle and to solve the security problem.

Analysis on the convection cooling process of crushed-rock embankment of high-grade highway in permafrost regions

Abstract As an important engineering measure for the proactive cooling frozen-soil roadbed, Crushed-rock embankment reduces the roadbed temperature by adjusting its heat convection process. An engineering test is conducted to study the actual application effects of the crushed-rock embankment in the condition of the widened highway. Results from monitoring ground temperature reveal not only the cooling process of the crushed-rock embankment, but also its actual cooling efficiency. The study results show that compared with the general embankment, crushed-rock embankment has a higher cooling efficiency and more obvious directionality of cooling process. It is found that through the first field monitoring of convection that 1) advection is the major convection mode in the crushed-rock layer, proving the leading role of heat convection in horizontal direction; 2) the advection intensity within the crushed-rock layer is largely limited to the width of subgrade, causing the temperature field under the left shoulder to be higher than that under the right; and 3) heat transfer process of the crushed-rock embankment changes with the seasons, the annual heat-flux density is − 0.07 W/m 2 , being a mild heat-releasing state, while the annual heat-flux density of the general embankment is 0.22 W/m 2 , being a stable heat-absorbing state. For high-grade highway characterized by wide asphalt pavement, the widening of embankment will inevitably further reduce the ventilation capacity of the crushed-rock layer, resulting in the loss of heat convection. Therefore, the separated construction or integrated control is the good choice for high-grade highway.

Root structure of slope protection plants in a high-grade highway

Root length and root length density of Lespedeza bicolor, Amorpha fruticosa, and Sea buckthorn were investigated in a country highway-TongSan highway (Tongjiang to Sanya) in Heilongjiang Province, China. The root lengths were divided into five root orders according to Pregizter sequence classification method. Results show that sea buckthorn roots are dominated by coarse roots in the horizontal growth, while L. bicolor has a large proportion of fine roots in vertical conical growth and A. fruticosa is in depth growth. Root length density of L. bicolor in all the root sequences is higher than that of sea buckthorn and A. fruticosa. On the basis of the root structure, it is inferred that L. bicolor roots mainly absorb the surface soil moisture for its normal growth; in contrast, A. fruticosa has good uptake ability to deep soil water. The root structure of sea buckthorn implies that it has a strong drought resistance.

The Model of Short-Time Traffic Flow Prediction on High-Grade Highway

In order to study the short-time traffic flow prediction on high-grade highway, the article proposed a model based on wavelet analysis and RBF neural network. Aiming to the traffic flow’s characteristic of highway, the study focus on three facet: network topology, the difference of continuous flow and discontinuous flow , the flow of lanes’ uplink and downlink are not equal. Thus the article use the wavelet analysis to do data preprocessing, then structure the model of short-term traffic flow prediction based on RBF neural network. The experiment result shows that the new hybrid model adapt to high-grade highway, and model considering traffic flow characteristic is better than the model which is not. Meanwhile the model has the higher precision of prediction.

Laboratory investigation on the cooling effect of crushed-rock interlayer embankment with ventilated ducts in permafrost regions

Abstract The engineering construction in permafrost regions would cause warming, even thaw of permafrost. This would bring thaw settlement damage and even failure to railway/highway embankments by exerting great influence on the embankment stability. Some traditional cooling measures have been proved to be effective on ensuring the thermal stability of embankment in the construction of the Qinghai–Tibet Railway. However, these cooling measures are applicable to the embankment of ordinary width, and would be unable to protect the underlying permafrost and ensure the stability of the high-grade highway embankment with multi-lane pavement. Due to the great heat intake caused by the asphalt-concrete pavement and a higher standard on settlement and uneven deformation, the permafrost problem is even more serious for high-grade highways of large-width than that for highway of ordinary width. To solve this new permafrost problem, traditional cooling measures should be either reinforced or combined. In this study, a new approach of a joint cooling measure consisting of crushed-rock interlayer and ventilated ducts was presented. A laboratory test was carried out to preliminarily investigate the effect of the new cooling measure. In the test, the temperature characteristics of two crushed-rock interlayer embankments with and without ventilated ducts are compared. The test results showed that the crushed-rock interlayer performed a more efficient cooling effect when the ventilated ducts are added than that when they are not added. The effect is direct: the performance of the ventilated ducts decreased the upper boundary temperature of the crushed-rock interlayer, and consequently enhanced its natural convection and cooling effect. Therefore, the crushed-rock interlayer embankment with ventilated ducts has a good cooling effect to the underlying permafrost, and should be recommended in the construction of large-width highways in permafrost regions.