Today, on my way to the construction site, I saw a construction site digging a foundation pit, so I asked Master about the knowledge of foundation pit excavation.

First, the process flow:

Determine the excavation sequence and slope → average excavation by sections and layers → trimming and bottom cleaning.

Second, the operation process

This project is an unsupported foundation pit (trough), and the slope must be put. The steepest slope should be 33%.

1, foundation pit (groove) excavation, reasonably determine the excavation sequence, route and excavation depth, and excavate evenly by sections and layers.

2. When the excavator moves along the excavation edge, the width of the machine from the upper edge of the slope should not be less than 1/2 of the depth of the foundation pit (groove) and pipe trench.

3, in the process of excavation, should always check the state of the groove wall and slope. Should be prepared for protection, in case of collapse.

4, excavation of foundation pit (groove) shall not be dug below the design elevation.

5. Earthwork that can't be dug by mechanical construction should be dug at any time with the help of manpower, and transported to the place dug by machinery by trolley so as to be dug in time.

6. Help clear the bottom. At the edge of the tank 50cm away from the design elevation of the tank bottom, find out the horizontal line, nail the Xiao Mu branch pipe, and manually dig the temporary soil layer. At the same time, both ends of the axis (center line) will pull the pile through the line (with small wire or lead wire), check the size from the groove edge, and determine the groove width standard. Trim the groove edge in this way, and finally remove the earthwork at the bottom of the groove. Quality inspection and acceptance shall be carried out after the tank bottom is repaired and leveled.

7. Due to the requirement of digging concrete cast-in-place piles, the earthwork stored on site should be piled up reasonably. When the site is stacked conditionally, leave enough good soil for backfilling; Excess earthwork should be transported away at one time to avoid secondary handling.

Third, the quality standard

The foundation pit (groove) and foundation soil of the site must meet the design requirements, and no disturbance is allowed.

Quality problems that should be paid attention to

(1) Overexcavation of basement: excavation of foundation pit (groove) shall not exceed the elevation of basement.

(2) The basement is not protected: the disturbance to the foundation soil should be minimized after the foundation pit (trench) is excavated.

(3) Insufficient excavation size and large slope: the excavation width and slope at the bottom of the foundation pit (trough) should be increased according to the construction needs in addition to the structural size requirements.

(4) Unreasonable construction sequence: Earthwork excavation should be carried out in strict accordance with the construction sequence specified in the construction plan, and attention should be paid to the excavation from the lower part first, and it should be carried out in layers and sections in turn to form a certain slope to facilitate drainage.

brick wall

Master continued to use the previous project to explain.

(3) Brick wall:

1) Masonry method: masonry generally adopts one shun and one ding (one full ding). Brick column masonry method shall not be adopted after four weeks.

2) Bricklaying at the bottom (dry bricklaying): When bricklaying at the bottom of the first external wall, two gables are built with cut bricks, and the front and rear longitudinal walls are built with long bricks. According to the position line of the window and door opening. Carefully check whether the size and length of the wall and stack between windows conform to the brick row module. If it does not meet the modulus, you can move the position of doors and windows left and right. If there is any broken work, these seven separate or small bricks should be arranged in the middle of the window, and battlements or other inconspicuous parts should be attached. When moving doors and windows, it should be noted that the heating and sanitation supervisor and the doors and windows are not affected when they are opened. In addition, when arranging bricks, it is also necessary to consider that the brick wall above the doors and windows will not be damaged when closed. Therefore, there must be a comprehensive consideration when arranging bricks. That is, when arranging each skin brick on the front and rear eaves, it is necessary to consider throwing the window before laying bricks. It is good to have seven independent corners on the window.

3) Brick selection: Bricks with neat edges and corners, no bending and cracks, uniform colors and basically the same specifications should be selected. When knocking, the sound is loud, and the bricks that change color and deform after baking can be used on the foundation and the inner wall that does not affect the appearance.

4) Slab angle: Slab angle shall be set before bricklaying, and the slab angle shall not exceed five layers at a time. The large angle of the new plate should be hoisted in time, and the deviation should be repaired in time. When setting the angle, carefully control the brick layer and elevation of the skin pole, control the size of the mortar joint, and make the horizontal mortar joint uniform. After the big horn plate is finished, check it again. Only when it is flat and vertical completely meets the requirements can it be hung on the wall.

5) Thread hanging: Double-sided thread hanging. If several people use a through line on a long wall, there should be several branch points in the middle, and the small line should be tightened. Each layer of brick should be threaded to make the transverse joints even, straight and smooth.

6) Bricklaying: Bricklaying shall adopt the "trinity" bricklaying method of one shovel of ash and one brick of one extrusion, that is, the full paving and extrusion operation method. When laying bricks, the bricks should be flat, the hands should be high and the walls should be open; If the hand is low inside, the wall will be backed. Bricklaying must follow the line, "upper with the line, lower with the edge, and the left and right neighbors should be flat." The thickness of horizontal mortar joint and the width of vertical mortar joint are generally 10mm, but they should not be less than 8mm or more than 12 mm ... During the operation, self-inspection should be carefully carried out. If there is any deviation, it should be corrected at any time. It is forbidden to hit the wall afterwards. Dry wall is not allowed to be divided into three parts, and it is not allowed to move or sew at will on the upper part. Masonry mortar should be used with mixing, cement mortar must be used up within 3h, cement mixed mortar must be used up within 4h, and overnight mortar is not allowed. Brick mortar drywall should be slotted with a seam depth of 8 ~ 10 mm, which is consistent and clean, and the mixed water wall should be leveled with tongue ash.

7) Leave a gap: the corner of the external wall should be laid at the same time. There must be a diagonal fork at the junction of the interior and exterior walls, the length of which should not be less than 2/3 of the wall height, and the fork must be straight. Segmented position should be at the deformation joint or door and window hole. When the partition wall and the wall or column are laid at the same time, embedded Rachel bars can be left. 2 Φ 6 steel bars are reserved for every 50cm of the submerged wall, and the embedding length is not less than 50cm on each side from the left corner of the wall, with a 90-degree hook at the end. The top of partition wall shall be extruded with vertical bricks.

Time: August 6, 2009-