Trenching refers to digging out the soil in the middle of subgrade to form a road groove, and discarding the dug soil; Slotting is to form two shoulders with soil piles on both sides of subgrade to form a road groove. Using this method, residual soil or retained soil can be used for filling. Half-excavation and half-filling is to excavate the road groove to the design depth of 1/2, and repair the excavated soil into a shoulder. Its width is the width of the structural layer under the pavement.
The depth of the extended data channel is calculated by the pavement structure, and the channel design elevation = pavement design elevation-pavement structure layer thickness. Road groove construction generally adopts grader to cooperate with manual leveling, and pay attention to line shape and elevation during construction.
Construction preparation work
(1) Preparation of lower bearing layer: After leveling and rolling, the indexes such as compactness, transverse slope and longitudinal slope meet the requirements and pass the inspection.
(2) Measuring and setting-out: The surveyors measure and set down the center line and sideline of the bearing stratum, and mark them with lime line.
(3) Test: Before construction, the lime shall be titrated.
Lime digestion
Lime should be piled up in the spacious site near the water source on both sides of the subgrade, and boiled with water according to the water consumption of 500~800 kg per ton of lime, and can be used only after the natural lime is completely digested for 7 ~ 10 days.
Material preparation and laying
Mark the unloading position of each vehicle with lime powder (draw a square), and directly and neatly unload the soil on the road trough. When preparing soil, it must be done vertically to ensure that the amount of soil transported by each vehicle is basically accurate.
First, roughly push the soil with a bulldozer for preliminary leveling, and then dry it with a rotary rake. When the water content of the soil reaches about 65,438+08%, it will be leveled with a grader, and the surplus part will be removed to make up for the vacancy, so as to achieve the effect of uniform thickness and smooth surface, and then it will be stabilized again with a roller to make it take shape.
Before making ash, the lime dosage per linear meter shall be calculated according to the ash dosage, the dry bulk density of lime loose square and the maximum dry bulk density of lime soil under different water contents.
The loose square dosage of lime per linear meter is divided into two ladder-shaped uniform yards for preparing ash, and the quantity is checked step by step with calipers, and then leveled by grader, with manual leveling, to achieve the effect of uniform ash distribution and consistent thickness.
Mixing: mixing is carried out by artificial uniform ash spreading and stabilized soil mixer, and the share is used as auxiliary equipment for mixing.
Shaping: After the mixture is stirred evenly, it will be leveled and shaped by grader. The test section is located in a straight line, and the grader leveled it from both sides to the center of the road, and then quickly rolled it on the newly leveled section with a roller to expose the potential unevenness, and then leveled it with the grader as before to achieve the best effect.
Rolling: after molding, in order not to miss the best rolling opportunity, when the water content reaches 18%, that is, the best water content +3%, rolling is carried out.
Health care: Sprinkling water for health care. During the curing period, traffic is closed, all vehicles except sprinklers are prohibited, and the surface of lime soil is always wet.
In lime-soil construction, it is necessary to constantly explore and summarize, analyze and compare the test data and results of each construction section, and then continuously improve and perfect the construction technology.
Baidu Encyclopedia-Cao Lu