Key words of the thesis: Expressway, embankment, construction quality, technical measures
Abstract: From the perspectives of design and construction, this article proposes several ideas and suggestions on how to ensure the construction quality of highway embankments, in order to provide reference for future embankment engineering construction control.
Everyone involved in road construction knows the critical role that embankment projects play in every road construction. If the quality of the embankment cannot be fully guaranteed during the construction process, with potential quality hazards, no matter how solid or hard the subsequent constructions such as pavement engineering and protective engineering are, they will not get fundamental guarantees. Therefore, the embankment project is an especially important part of all components of road engineering. We must take a series of scientific measures to ensure its quality during the construction process. Especially in today's era of "high-quality, high-standard, high-demand" highway construction, we should be more cautious and better ensure the quality of the embankment. To ensure the quality of embankment construction, making it comply with the design and specification technical requirements, and satisfying the design functions well, we must reasonably design it according to different geological conditions and construction requirements, and strictly implement it according to the construction specifications so that the construction quality can be adequately guaranteed. Below, let us understand some common quality assurance measures for embankments from aspects such as design and construction.
1 Technical Measures in the Design Process
1.1 Conduct detailed geological investigation and survey on the topography, geomorphology, and hydrogeological conditions along the route, especially providing detailed design data for special embankment sections. The design can consider soil replacement or adding lime, cement, and laying geotextiles for sections with poor surface conditions.
1.2 Ensure the minimum filling height of the embankment. The minimum filling height of the embankment must ensure that its stability is not reduced due to the influence of surface water, groundwater, capillary water, and frost heave. According to the requirements of the embankment design specifications, based on the dry-wet type of the soil foundation and the height of the capillary water level, ensure the minimum filling height of the embankment. When the embankment filling height is restricted and cannot reach the specified standard, corresponding treatment measures should be taken, such as replacing sand and gravel, crushed stone and other permeable materials, setting up isolation layers or constructing underground seepage ditches to prevent surface water and groundwater from infiltrating into the embankment, affecting the strength and stability of the soil foundation within the working area of the embankment. For soil excavation embankments, at least 60 cm of sand and gravel must be replaced; for rock excavation embankments, a 30 cm sand and gravel cushion layer must be set up. Sections with poor lateral drainage should add blind drains.
1.3 Clearly define the quality standards for embankment fill materials. In the construction drawing design of all levels of road projects, the CBR value (minimum strength) and maximum particle size requirements for embankment fill materials at different filling heights must be clearly defined. Poor-quality soils such as planting soil, organic soil, silt, frozen soil, and highly expansive soil are strictly prohibited from being directly used for embankment filling. Gravel (angular gravel) class soils should be preferentially selected as bedding fill materials, and poorer fine-grained soils can be filled at the bottom of the embankment.
1.4 Improve comprehensive embankment drainage design. In county-level and above road engineering design, the principles of adapting measures to local conditions, overall planning, and comprehensive consideration must be followed for longitudinal and transverse embankment drainage design to avoid long-term water accumulation soaking the embankment on both sides, reducing the bearing capacity of the embankment and causing settlement deformation. Drainage side ditches must be set up in village sections, and side ditches in flat slope sections must have longitudinal slopes to ensure smooth drainage. High-fill sections adopt centralized drainage methods and are comprehensively considered with warning piles and crash walls, requiring simple or permanent water discharge grooves to be set up every 20-40 meters and at major slope change points. The interception ditch for cut sections is designed based on the catchment area of the upper slope and considers the soil quality and slope of the slope, setting retaining walls to prevent collapse. For low embankment sections, measures such as adding gravel layers and seepage blind ditches, and increasing and deepening side ditches can be adopted.
1.5 Ensure the stability of embankment slopes. The slopes of high-fill and deep-cut embankments should be determined according to the type of fill material, slope height, and engineering geological conditions, and the stability calculation of high-fill embankments must be carried out. When the fill slope is too high, slope platforms can be considered in the middle of the slope.
1.6 Actively adopt comprehensive embankment protection forms. Promote the combination of plant protection and hard protection in comprehensive protection forms. On relatively stable soil slopes, grass seeding, turf laying, tree planting, and other plant protection measures can be adopted. For severely weathered rock masses, developed joints, soft rocks, loose gravel (gravel) stone soil cut slopes, and fill slopes affected by water erosion where plants are difficult to grow, engineering protection measures such as facing walls and masonry stones can be adopted. Along-river embankments and sections subject to ice damage and scouring can adopt direct protection measures such as retaining walls, masonry stone slopes, and stone cages.
2 Technical Measures in the Construction Process
2.1 Do a good job in construction organization design, reasonably arrange the sequence of construction sections, clarify the connection relationship between structures and embankments, and prioritize the construction of high-fill sections. In the construction process, take the construction organization design as the leader, reasonably allocate personnel and equipment according to the actual situation of the construction site, which is an important link in ensuring the quality of high-fill embankment construction.
Related theme articles: ONOOOQQOOMNNQNMLMMMRRQSO
Zhao Banzhang and his team enthusiastically played shuttlecock outside Liu Xiaohua's house again.
No matter how much you pay...