Technical disclosure data of earthwork

1 This technical disclosure is applicable to the earthwork of CITIC Kaixuan An Lan Garden Phase II (North Zone).

2 Overview of earthwork excavation

The scope of this earthwork excavation is villas, high-rise buildings and multi-storey buildings in the north area. The relative elevation of some villas is about -2.7 1m, and the relative elevation of multi-high-rise buildings is about-4.66m. The elevation of some foundation caps of villas is -2.4m, the elevation of the bottom is -3.2m, the excavation depth of some villas is 0.3m~0.5m, the elevation of some foundation caps of multi-high-rise residential buildings is -3.7 m ~-6.2 m, and the elevation of the bottom of caps is-4.2m.

List of excavation depths of high-rise and multi-storey pile caps

Pile cap height (mm) Quantity surface elevation (m) Bottom elevation (m) Site elevation (m) Excavation depth (m)

J4-4a 4 -3.7 -4.9

-4.66 0.34

2 1200 J2-4b

3 1200 J5 4a 8-6.2-7.4 2.84

4 1200 J2-4a 16-4.8-6.0 1.44

5 1600 J2 5b 8-3.7-5.3 0.74

6 1200 J2-4b

7 1200 J5-4b

8 800j 1-4a 2-3.9-4.7 0. 14

J2-5c 8-5. 15-6.75 2. 19

J2-5b 60-5. 15-6.75 2. 19

J2-4c 4 -5. 15 -6.35

12 1200 J2-4a 12-5. 15-6.35 1.79

13 800j 1-4a 12-4.55-5.35 0.75

14 800j 1-4a 8-5. 15-5.95 1.39

15 1200 J2-4c 102-5. 15-6.35 1.79

JBOY3 -5b 8 -5. 15 -6.75

2. 19

J2-5a 6 -5. 15 -6.75

JBOY3 -5c 6 -5. 15 -6.75

J2-5b 4 -5. 15 -6.75

201600 J3 -5d 12 -5. 15 -6.75

2 1 1600 J4-5a 12-5. 15-6.75

22 1600 J4-5b

231600 J3 -5a 10 -5. 15 -6.75

24 1600 J5-5b 2-5. 15-6.75

251600 J3 5e 10 -5. 15 -6.75

26 1600 J6-5b 12-5. 15-6.75

27 1600 J5 5c 2-5. 15-6.75

28 1600 J4-5c 12-5. 15-6.75

4.66

2. 19

29 1600 J4-5d 2-5. 15-6.75

30 1600 J7-5a 2-5. 15-6.75

3 1 1600 J9-5 2-5. 15-6.75

32 1600 J7-5b 2-5. 15-6.75

33 1600 J8-5 6 -6.2 -7.8 3.24

List of Excavation (Backfill) Depth of Ground Beam

No. Plate thickness (mm) Plate surface elevation (m) Plate bottom elevation (m) Site elevation (m) Excavation thickness (m) Backfill thickness (m)

1 150 -4.45 -4.6

-4.66 0.04

2 150 -3.3 -3.45 1. 1 1

3 150 -3.0 -3. 15 1.4 1

4 150 -4.65 -4.8 0.24

3 main machines and tools:

3. 1 Earthmoving machinery includes: PC 120 excavator is used for earthmoving machinery, and small excavators are needed for deep foundation pit excavation.

3.2 General machinery includes shovels (pointed heads and flat heads), trolleys, small white wires or 20 # lead wires, steel tape measure, level gauge, tower ruler and slope scale.

3.3 Operating conditions:

3.4 Before earthwork excavation, the underground and ground obstacles in the construction area shall be cleaned and treated according to the requirements of the construction plan.

3.4 The dimensions of the position control line (pile), standard horizontal pile and slotted grey line of the building must be inspected; And complete the pre-inspection procedure.

3.5 During construction at night, there should be sufficient lighting facilities; Dangerous areas should be clearly marked, and the excavation sequence should be arranged reasonably to prevent wrong excavation or overbreak.

3. When the construction excavator comes into play, the facilities such as roads should be checked in advance to prevent pile squeezing, and it is strictly forbidden to pass directly from the pile.

3.7 The layout of regional operation routes shall be excavated in the order of earthwork excavation provided by the project department, and excavation shall not be carried out at will.

3.8 Mechanical construction, slope repair, groove bottom cleaning and other inoperable parts. Are equipped with manpower.

4 process flow:

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

Five preventive measures:

5. 1 Slope protection:

5. 1. 1 optical cable protection

Unicom communication optical cable is buried on the south side of Century East Road in North District. The shortest distance between the optical cable and the bearing platform of B23 and B24 buildings is 5m, and the excavation depth of the bearing platform is 2.2m (local excavation is 1.8m). The thickness of plain fill in this area is 1.36~5.7, and most of the excavation faces are located in plain fill layer. In order to prevent the influence of earthwork excavation in this area on optical cables, the 23-R axis and the 24-R axis.

5. 1.2 Villa slope protection:

Due to the small excavation depth of the pile caps in the villa area, the excavation depth is generally 0.3m~0.5m, and the earthwork excavation should be properly graded (the grading coefficient is 1: 1), and the excavation width at the bottom of the foundation pit is the foundation width (20cm is reserved on each side).

5. 1.3 multi-layer and high-rise slope protection

(1) Slope protection of elevator shaft:

The excavation depths of multi-storey and high-rise elevator shafts are 2.8m and 3.2m, which are relatively deep. Moreover, due to the high groundwater level, the bottom of some caps is lower than the groundwater level, and the slopes of multi-storey and high-rise elevator shafts are supported by cement soil walls. Mixing piles are arranged in a row and a half, and the mixing piles need to be constructed along the outer edge of the bearing platform, and earthwork excavation can only be carried out after the mixing piles reach the setting period.

(2) Other pile caps and ground beam slope protection:

For multi-storey and high-rise pile caps (except elevator shafts), the excavation depth is 0.34m~2. 19m, the excavation depth of ground beams is 0.04~0.59m, and some ground beams need to be backfilled 0.86m ~ 0.96m Before the pile caps with the excavation depth of 2.2m are excavated, channel steel is driven around the pile caps every 1m for temporary protection. For the foundation pit with excavation depth of 0.34~ 1.8, the slope should be properly laid (the slope laying coefficient is 1: 1). The excavation width at the bottom of the foundation pit should be the width of the foundation (20cm is reserved on each side). In case of water gushing, sand gushing and collapse during excavation, sand bags shall be used for slope protection, and the excavation width at the bottom of foundation pit shall be the foundation width (40cm shall be reserved on each side).

5.2 Brick membrane support

The sidewall of the built deep pit cap should be supported with wooden fang and steel pipe in time to avoid deformation or collapse of the sidewall tire membrane caused by excessive earth pressure. The concrete way is to place the retaining plates on both sides horizontally, push the wedge tightly with tool-type or wooden cross braces, and dig a layer of soil to support the top floor. In addition, due to the large lateral pressure of the soil when backfilling, the earthwork should be backfilled after the brick wall reaches a certain strength, and lightly rammed with a wooden hammer or a wooden fang in layers (200-300mm/ layer) to avoid crushing the brick wall.

5.3 Drainage measures in the site area

5.4 Precipitation measures within the site

(1) core cap dehydration

Because the bottom elevation of multi-storey and high-rise pile caps (core tube area) is below the groundwater level, dewatering and drainage are particularly important during construction. The collecting well is initially set at the bottom of the core pipe cap. According to the specific situation on site, if the groundwater is very rich, it can be replenished continuously.

(2) Precipitation of other caps and ground beams

There is a 300×300 temporary sump at the bottom of the pile cap, and the excavation depth is large, so submersible pump is used to pump water to the adjacent drainage ditch.

5.5 Drainage measures in site area

During earthwork excavation, considering the rich groundwater and other reasons, a water retaining sill is set at the top of the foundation pit to prevent rainwater from flowing into the foundation pit. The water retaining sill is built with lime-sand brick, and the inside is plastered with 20-thick 1: 2 cement mortar.

According to the actual situation of the site, a collecting well and an open ditch are set in the site. Before earthwork excavation, drainage ditches and collecting wells should be built to ensure smooth drainage in the site. Set drainage ditches on both sides of temporary construction roads and around the site, and set up collecting wells and grit chambers. At the same time, make full use of the drainage ditch around the site to form a drainage pipe network, and discharge the accumulated water in the site to nearby Hanoi or municipal pipe network. Drainage ditch, collecting well, grit chamber and municipal pipe well are connected by D200 PVC pipes, and some parts that need vehicles to pass through adopt prefabricated drainage pipes. .

6 earthwork excavation construction requirements

(1) During earthwork excavation, mechanical excavation will be adopted, and the foundation pit will be excavated above the elevation of pile top and ground beam bottom 100mm, and then manual excavation will be adopted, which will be horizontally transported to both sides of ground beam pile top with a bucket truck, evenly filled and compacted. At the same time, attention should be paid to the excavation according to the pile foundation construction completion drawing and pile delivery record to avoid wrong excavation. When the excavator digs near the pile body, the foreman and soil sweeper should strictly supervise it, and it is absolutely forbidden for the excavator to dig into the pile body and have a lateral collision with it.

(2) In the process of excavation, the elevation must be measured at any time, and the excavation depth should be controlled to prevent over-excavation and under-excavation. At the same time, it is necessary to ensure the accurate position of the bearing platform, and the earthwork should be cleared with the excavation.

(3) After earthwork excavation, drainage and cleaning shall be carried out in time to ensure smooth grass-roots level, and concrete cushion shall be poured immediately. Cushion casting width should be 200mm wider than brick mold (cushion width = foundation width+brick mold thickness +400mm). After the cushion concrete is solidified, the edge of the bearing platform will be released, and the brick membrane will be laid. After the brick membrane reaches a certain strength, backfill the earthwork of the slope of the bearing platform, and the backfill soil must be compacted in layers. Pay attention to the stability of brick membrane when pressing.

(4) In the process of foundation pit excavation, we should pay close attention to the deformation of surrounding slopes and roads, and monitor the displacement and settlement of foundation pit slopes and adjacent buildings. When problems are found, we should stop digging in time and study solutions, and take effective treatment measures to ensure the smooth progress of the project and construction safety.

7 earthwork backfilling

7. 1 beam and slab backfill

There is earth fill in the south of the multi-storey residence, and the backfill depth of beam is 0. 1m~0.85m, and the backfill depth of bottom plate is 0.15m ~1.6m.. Because the upper part of the original basement soil is backfill, but the thickness is thin and the lower part is silt, this kind of soil has poor stability and bearing capacity, and is not suitable for backfilling pile caps, ground beams and grooves. If this kind of soil cannot meet the requirements of backfilling after air drying, it must be transported abroad (high-quality clay) for backfilling. Before backfilling the site, the garbage, turf and tree roots on the basement should be removed first, and the accumulated water and sundries in the pit should be removed. When backfilling, it should be tamped by layers to prevent the brick film from being squeezed.

7.2 Excavation and backfilling of pile extension part

Considering that the excavation of pile extension will disturb the bearing stratum around the pile foundation, and the soil quality of the original soil layer is poor, if the water content of this kind of soil can not meet the requirements of backfill after drying, it is necessary to backfill with foreign clay, reduce the thickness of primary backfill and strengthen compaction.

8 vehicle driving route during earthwork excavation

Due to the need to transport part of soil during earthwork excavation, piles are densely distributed in high-rise and multi-storey buildings. In order to prevent the piles from shifting due to the position of piles where vehicles are driving, vehicles in the field should stay away from the pile caps with many piles. Earthwork excavated in the high-rise part is stacked on the north side of the high-rise, earthwork excavated in the multi-storey is stacked on the south side of the multi-storey, and the main earthwork excavated in the middle is stacked in the garage.

9 slope landslide

9. 1 If there are signs of landslide (such as cracks, sliding, etc.) during earthwork excavation. ), the following measures should be taken immediately:

A, suspend construction, when necessary, transfer all personnel and machinery to a safe place;

B, immediately notify the emergency team leader, and quickly take treatment measures, such as using excavators to quickly backfill at the foot of the slope (arrange excavators to stand by at any time);

C, according to the signs of sliding, set observation points, observe the plane displacement and settlement changes of landslide, and make records. Strengthen displacement observation, once every two hours, and report and sort out the data in time.

9.2 local collapse

In the process of earthwork excavation, if plain fill and silt are exposed for a long time, they will easily lose water and peel off when disturbed. When the slope collapses, temporary support (such as stacking soil woven bags or straw bags, setting supports, laying slope protection walls, etc.) can be carried out by removing the collapsed slope toe. ).

9.3 surface crack

During the whole construction and excavation process, the cracking and deformation of the adjacent surface should be continuously observed, especially at the communication optical cable on the south side of Century East Road. Under normal circumstances, small cracks on the surface can be regarded as normal, but the development trend must be closely followed and special treatment measures should be taken in time. When the cracks develop and expand rapidly, the original construction technology should be suspended, the supporting parameters and reinforcement should be modified in time, and other supporting methods should be added if necessary.

10 guarantee project:

10. 1 The foundation soil of pile caps, ground beams and sites must meet the design requirements, and no disturbance is allowed.

See table l-5 for the allowable deviation items of 10.2.

Table 1-5 Allowable deviation of earthwork excavation and site leveling

Test method for allowable deviation (mm) of serial number items

1 Surface elevation +0 is not allowed.

2 length, width -50 level check.

3 steep slope -0 with theodolite, stay, ruler check observation or check with slope scale.

10.3 is used to locate standard piles, axis guide piles, standard leveling points, etc. When digging and transporting soil, collision is not allowed. And should often measure and check whether its plane position, horizontal elevation and slope meet the design requirements. Positioning standard piles and standard leveling points should also be retested regularly to check their correctness.

10.4 Overexcavation of basement: excavation of foundation pit (groove) shall not exceed the elevation of basement. If there is over-excavation in some places, the treatment method should be approved by the design unit, and it is not allowed to treat it privately.

1 1 rainy season construction measures

(1) Before the rainy season construction, our company will make a rainy season phased plan according to the site conditions and the progress of the project, and report it to the owner and supervision engineer for approval before implementation.

(2) Around the top of the foundation pit, build a water retaining sill with a height of 200 and a thickness of 120 (both inside and outside are plastered with 1: 2 cement mortar), and make a slope with a width of about 20cm outside the water retaining sill to prevent rainwater from entering the foundation pit.

(3) The ground around the pit should be filled with a certain slope, and a drainage system should be formed by using the on-site drainage ditch and collecting well.

(4) In view of the fact that this project is located near the original building and is rich in groundwater, we should attach great importance to it when the rainy season comes, study countermeasures in time, and make supplementary plans to ensure the normal construction of the structure.

(5) Strengthen the duty in rainy season, listen to the weather forecast, clean the puddles and drains in the pit before it rains, prepare pumping tools such as submersible pumps, organize manpower and material resources to pump and drain the pit in time after the rain, and dredge the accumulated water around the foundation pit.

(6) Ground drainage: In order to prevent the foundation pit from flooding, drainage ditches, drainage ditches, water cut-off dikes and culverts should be set around the foundation pit or upstream of running water in advance during the foundation pit excavation and basement structure construction. In order to prevent foundation pit collapse and landslide caused by rain in rainy season, drainage pipes (similar to drainage holes of retaining walls) should be set at regular intervals on the side wall of foundation pit while well draining the ground.

(7) Drainage of foundation pit: In order to prevent surface water and groundwater from infiltrating into the foundation pit, causing the foundation pit to be flooded, destroying the slope stability and affecting the construction, measures such as intercepting groundwater and drainage in the pit must be taken. Drains and collecting wells can be set outside the structure around the bottom of the foundation pit. The width of the drainage ditch is 0.3m, the depth is 30-50cm, and the slope is 0. 1-0.5%. The accumulated water in the collecting well should be pumped out at any time to ensure that the bottom of the foundation pit is dry.

(8) Strengthen the monitoring of foundation pit and the observation of water level in the pit after rainy days, and take timely measures to ensure the safety of foundation pit support and drainage works in case of abnormal conditions to meet the construction needs.

12 safety protection, civilized construction and environmental protection

(1), construction personnel must strictly abide by the rules and regulations of safety management on the construction site and formulate measures to prevent falling and collapse.

(2) During earthwork excavation, it is forbidden to pile up heavy objects or drive heavy vehicles within the pit edge 1m; The installation and use of power lines and facilities in the construction site must meet the management standards for temporary electricity consumption, and the site lighting should be guaranteed at night, and a warning red light should be set at the pit.

(3), mechanical and electrical equipment must be operated by certified personnel, and in accordance with the provisions, do a good job in maintenance. During earthwork excavation, observe whether the surrounding buildings and roads are deformed and cracked. If suspicious problems are found, they should be reported to the project department in time for processing.

(4) Vehicles must be cleaned when leaving the construction site. Before all vehicles enter the city roads, they must be cleaned at the car washing platform set at the gate to prevent dirt from being brought to the city roads. At the same time, ensure that the earth-moving lane on the construction site is unblocked and there is no water on the site.

(5) The site shall be equipped with necessary fire prevention equipment and kept in good condition.

(6), the site materials must be neatly stacked.

(7) Conduct regular safety education and set up safety construction slogans at the entrance of the construction site.

(8), artificial cooperate with mechanical digging operation, personnel are not allowed to enter the excavator operation radius, must enter, after the excavator operation stops, personnel can clean up the basement and find equal slope operation.