Insights and Findings Following 11 Years of Test Road Exploitation

Road pavement is one of the most important components of road structure. Long-term monitoring changes in the state of road pavement under real conditions of load and climate allows to determine surface degradation mechanisms, select sustainable road building materials and their mixes, rationally employ asphalt paving technologies, and improve quality control. For a number of years, road pavement structures have been studied that should best meet the Lithuanian climate conditions and withstand the increasing impact of vehicle load. Thus, for that purpose, specially designed, constructed and tested roads or road sections for different pavement structures are most appropriate. One of those was constructed in 2007. The experimental road (hereinafter, the Test Road) consisted of 27 different pavement structures (PSs) produced of various materials. The study aims to evaluate the effect of different materials on variations in the bearing capacity of the pavement structure (PS), the sustainability of the structure, and the formation of ruts in 2007–2018. In this way, difference in bearing capacity, rutting depth between sections, and loaded and unloaded lanes was estimated. Further, the statistical analysis of these factors was conducted. Investigations have shown that the minimum bearing capacity of 754 MPa established after 11 years did not affect the formation of rut depth that was less than 1.0 cm. The PSs covered with the used asphalt granules, a larger asphalt base course on gravel, the sand mix base course, and granite aggregate mixed with sand base course were accepted as one of the PSs with the highest bearing capacity with PSs exceeding 929 MPa. The bearing capacity of the PS containing a 20 cm aggregate base course is on average higher by 30 MPa than PS holding a 15 cm aggregate base course.

Comparative Analysis of Windy Accumulated Sands by Heavy-Typed Compaction and Surface Vibration Compression Method of Desert Areas in China

Windy accumulated sand samples are collected in the main desert (Sandy land) in China, they are carried out the comparative tests by heavy-typed compaction and surface vibrated compression method. The results show that the effect of surface vibrated compression is stronger than that of heavy-typed compaction in general, especially when the water content is approaching to 0 or the saturation state, the former is greater than the latter by about 1g/ cm3; When the water content is about ranging from 1 % to 5 %, the former is still mostly higher than the latter, yet not much and the most is under 0.3 g/ cm3, even the former is slightly lower than the latter sometimes; When the water content is within other intervals, it shows a transitional situation. The main reason is the influence of false cohesion arising from the capillary water. In view of this, when determining the compression standard (maximum dry density) for the construction of wind-accumulated sand base, the surface vibrated compression method should be adopted, especially when it is dry compression or full water compression.

BEARING CAPACITY OF MODEL FOUNDATIONS ON SANDY GROUNDS

The article continues the review of experimental studies conducted by the scientific school of soil mechanics of Novocherkassk Polytechnic Institute from 1962 to the present time. Studies of the bearing capacity of the sand base were carried out on various models of line, round, stand-alone and under the grid columns (plate).

Unconscious decisions causing a failure condition of the 19th century brick ceiling

The article describes a hazard caused by deformation of a brick vault located under the dungeons of the gate tower of Zamek Górny in Opole at the turn of the 13th and the 14th centuries, which was used as a school building until 2017. The hazard identified in 2013 was found on the ground level of the building in a communication route of the heavy traffic load. Visual inspections and tests have demonstrated that the existing situation was caused by civil works performed at the dungeon level nearly 6 years earlier due to an unconsidered decision on removing debris and a backfill which filled entirely the lower tower storeys. The above actions resulted in removal of the base of the floor ‘laid on the ground’ in the 19th century [2][4]. In this article, an analysis was carried out to verify possibilities of unbelievable strength of the artificially formed flat vault, which was previously the floor supported on a debris and sand base.

EXPERIMENTAL STUDY OF STILLING BASIN MODELS

Stilling basins with appurtenances can be used effectively in dissipating the excessive energy downstream of hydraulic structure like spillway, sluices, pipe outlets etc. Experimental investigation leading to the development of new stilling basin model design for pipe outlet with different appurtenances is reported in this paper. On the basis of present study, newly stilling basin design has been compared with USBR VI model. The new models were tested in a rectangular shaped pipe outlet for three Froude numbers, namely Fr = 1.85, 2.85, and 3.85 in comparison to USBR VI stilling basin model recommended for the pipe outlets. The scour pattern was measured for each test run and flow pattern was also observed. The performance of the basin was compared by Performance number (PN) as criteria to evaluate the performance of model, using same sand base material and test run time for all the tested models. After test runs, it is found that, for a given Froude number range, the performance of new stilling basin model is improved and also the length of the newly developed basin is reduced as compared to USBR VI stilling basin for a given flow conditions.