When there is a pipeline in the site when the earthwork is backfilled, how to prepare the earthwork

Backfill medium sand, can not use machinery, must be manual backfill.

1) Common quality problems.

The soil quality of the water with the same fill or backfill does not meet the requirements; There is no layered backfilling; The density of the backfill is not strictly controlled.

2) Quality control measures.

1.Strictly control the quality of the backfill soil. The backfill shall not contain broken bricks, stones, concrete fragments and hard soil blocks greater than l0cm; The moisture content of the fill soil should be close to the optimal water content.

Before returning to the soil, a light standard compaction test should be carried out to determine the optimal water content and maximum dry density of the returned soil. There should be no stagnant water in the tank when backfilling, and no silt, humus, frozen soil and organic matter should be backfilled.

2.Strictly control the thickness of each layer of backfill. The pipe trench backfill should be layered and tamped, and the thickness of each layer should not be more than 30cm, and the compactness of each layer of filling should be tested according to the specification, and the backfill can only be continued if it is qualified; It is required that both sides of the pipeline be filled at the same time, and the height difference between the two sides is not more than 30cm

3.Strictly control the compactness of the backfill. The compactness of the thoracic cavity of the canal groove is not less than 90%; The compactness within 50cm of the top of the pipe should be between 85% and 88% to prevent crushing the pipe and cover plate The compactness of the pipe item above 50cm is required to be the same as the compactness of the roadbed.

Drainage pipeline engineering is a concealed project, only to strengthen the quality control of all aspects of the construction process, in order to prevent the occurrence of various quality problems, to ensure that the overall construction quality of the project to achieve excellent.

The common problems and measures of backfill in municipal pipeline engineering are as follows:

Problem: The quality of the backfill is substandard, containing a large number of impurities and organic matter.

The thickness of the backfill layer is uneven, and there are cavities and incompactness.

The backfill is not in close contact with the pipeline, and there is a risk of displacement and deformation of the pipeline.

The construction of backfill soil is not standardized, and there are poor construction quality and potential safety hazards.

Measures: Select reliable quality backfill soil, carry out adequate screening and treatment to ensure that the soil quality meets the requirements.

Before the backfill construction, sufficient foundation treatment and reinforcement are carried out to ensure that the soil layer is uniform and compact.

In the process of backfill construction, appropriate compaction methods and tools are used to ensure that the backfill is in close contact with the pipeline.

Carry out construction in strict accordance with the design requirements and construction specifications, strengthen on-site management and supervision, and ensure construction quality and safety.

Content from user: Huang Ge.

The earthwork of the 15th floor of the second phase of Dongchen Mingdu.

Backfill schemes. Compiler: Xiong Panwang.

Reviewer: Xu Yongsheng.

Preparation unit: Dongchen Mingdu Phase II 15th Floor Engineering Project Department.

May 10, 2016.

New Oriental Community Phase I Project Foundation Earthwork Backfill Scheme.

First, the general situation of the project.

This project is the second phase of the Dongchen Mingdu project in Jingde County, with a construction area of about square meters, the number of layers of the project building, the storage room is meters high, and the standard layers are, the project is a frame structure, the foundation is a raft foundation, and the foundation bearing layer is the first layer of strong wind granodiorite, and the characteristic value of the bearing capacity of the foundation is 875kn, and the limit value of the bearing capacity is 1750kn. The foundation is buried deep in meters, and the foundation construction task has been completed, and the following are backfills, ready to be backfilled. The building is classified as Class II, with a fire resistance grade of Class II, a seismic fortification intensity of 6 degrees, and a roof waterproof grade.

1. Foundation concrete (bearing cap, beam, column), the foundation has been completed.

2. There is no overhead layer on the bottom plane, and the bottom is backfill.

Second, the backfill scheme:

Because the construction period of this project is tight, and the construction is in winter, if the thickness of the design layer layer 300 is layered and compacted, the progress of the project, the density of the backfill can not meet the requirements, so the foundation backfill adopts the phased backfill tamping

The first stage is backfilled to the top surface of the cushion cap foundation beam, the second stage is backfilled to the cushion cap, the foundation beam is 500mm The third stage is backfilled to the lower 500mm, and the fourth stage is backfilled to the ground stage of the decoration building. The specific construction is as follows:

1. The first stage: within the cantilever arm of the backhoe near the periphery of the foundation, the mechanical backhoe is used to backfill, and the small excavator outside the cantilever arm is used to transfer, backfill to the cushion cap and the foundation beam surface, and the surface layer is tamped. 8