8
. 
Therefore, when the waist beam adopts reinforced concrete waist beam, the contact surface between the waist beam and the support structure must be roughened and planted with reinforcement; When the waist beam adopts section steel, the embedded parts of the section steel and the supporting structure shall be welded, or the section steel and the supporting structure shall be filled with concrete to ensure uniform stress on the contact surface between the waist beam and the supporting structure（ 3) Whether the water stop structure can meet the water stop requirements
.
Whether the edge protection is carried out around the foundation pit support according to the regulations; Whether the safety passage of foundation pit meets the requirements; Check the safety protection and safe passage of the site foundation pit
.
According to the relevant provisions of technical code for building foundation pit support jcj120 and technical code for safety of earthwork engineering in building construction jgj180-2009
. 
7
.
The upper and lower layers of the same vertical working surface shall not be operated at the same time
.
Whether routine testing of raw materials and test blocks (pieces) has been carried out; Check the test results
.
Special stairways for constructors to go up and down should be set in the foundation pit
.
3
. 
During construction, it is strictly prohibited for equipment or heavy objects to collide with foundation pit support structures such as support, waist beam and anchor bolt
.
1
. 
the construction quality of such structures is sensitive and prone to quality problems, which should be paid great attention to
.
In the construction of foundation pit engineering, the construction unit will directly face the construction safety
.
Whether the water stop structure can meet the water stop requirements is not only one of the important factors for the smooth construction of foundation pit and engineering pile, bearing platform and bottom plate, but also one of the important factors for the safety of the surrounding environment in the process of foundation pit construction
. 
Whether the company and project safety inspection has been carried out; Check the inspection records（ 2） The key points of safety management of the construction unit are mainly in accordance with the relevant provisions of technical code for safety of earthwork engineering in building construction (jgj180-2009)
.
5、 The whole process of deep foundation pit construction 6、 There is no doubt about the key points of safety management of the construction unit of deep foundation pit engineering
.
At present, the commonly used water stop structures in foundation pit engineering are mixing pile water stop curtain, rotary jet grouting pile water stop curtain, etc
.
The cross bars shall be set with 2 ~ 3 courses, the lower bar shall be 0.3m ~ 0.6m above the ground, and the upper bar shall be 1.2m ~ 1.5m above the ground; The distance between poles should not be greater than 2.0m, and the distance between poles and slope edge should be greater than 0.5m; The protective railing should be hung with dense mesh safety net and toe board
.
Source: in case of infringement of Wenzhou Central building project and network data of China Construction First Bureau, please contact to delete the first part Preface I
.
Whether the stacking load at the pit side is less than the design requirements; Check the stacking of materials, machines and tools near the pit
.
Except as permitted by the foundation pit support design, no soil, materials or machines and tools shall be stacked near the foundation pit
.
It belongs to a large foundation pit
. 
Check whether the emergency plan measures 7.1 special plan has formulated the emergency plan measures and whether the measures are targeted; Check the contents of emergency plan measures
.
6
.
Check the edge safety protection
. 
Check whether the construction operation has cross influence
. 
the slope of foundation pit collapse accident is not enough, and the slope is not conducted according to the specified slope according to the soil category and allowable value of slope
. 
4、 Overview and characteristics of foundation pit support of the project the foundation pit area of the project is about 46350 ㎡, about 170m long in the east-west direction and about 228m in the north-south direction
.
The protective railing shall be firmly installed, with a height of no less than 1.2m, and shall be composed of cross bars and vertical bars
.
The height of toe board should not be less than 180mm, and the height from the lower edge of toe board to the ground should not be more than 10mm
.
Handrails shall be provided for the stairway, and the width of the stairway shall not be less than 1.0m
.
It is strictly prohibited to excavate in advance and over excavate
.
4.1
.
Check the earth excavation construction
. 
2
.
Protective railings must be installed around the deep foundation pit, and follow up in time during foundation pit excavation
.
Sufficient lighting measures and safety warning signs shall be provided on the working surface and access roads at night
. 
Whether the special scheme is consulted and demonstrated as required; Check the expert argumentation opinions of the special scheme
. 
4.3
.
The cohesion of soil mass is destroyed by overloading or vibration at the top of foundation pit slope, resulting in the destruction of soil structure
.
5
.
Whether the excavation is carried out according to the requirements of the approved special scheme for earth excavation, whether the excavation is carried out according to the specified procedures, and whether there is over excavation
.
To be determined by detection; If the pile quality cannot meet the requirements, measures shall be taken for reinforcement（ 2) Whether the connection between waist beam and support structure can meet the design requirements
. 
The total extension line of the foundation pit is 926m, the basement is three floors, and the excavation depth of the foundation pit is 12.5m, 13.6m and 14.6m respectively
.
4.2
.
Natural disasters, etc
.
The construction method is incorrect, the excavation procedure is incorrect, the over elevation excavation, the support setting or removal is incorrect (the construction is not carried out according to the scheme), or the drainage measures are ineffective (including dewatering operation)
.
Whether the excavation machinery damages the support structure and affects the support safety; Check whether the on-site excavation equipment has damage and damage to the foundation pit support
.
Concept III
.
Heavy objects shall not be placed or hung on the supporting structure
.
When it is necessary to operate at the same time, isolation and protection measures shall be taken between the upper and lower layers
.
Between the waist beam and the supporting structure, it is necessary to ensure that the waist beam can transmit both horizontal force and shear force
.
9
. 
Key points for behavior inspection of the responsible subject of the construction unit 1
.
The inspection and acceptance shall be carried out according to code for acceptance of construction quality of building foundation gb50202-2002
. 
The safety net should be closed from top to bottom
.
After hail, heavy rain, heavy snow, strong wind of level 6 or above and other bad weather, the foundation pit and safety facilities shall be inspected in time.
.
3
4
.
Whether a special construction scheme is prepared; Check the special scheme for support and earth excavation
.
The project is adjacent to Oujiang River in the west, close to the ditch in the East, with high underground water level, close to civil houses in the north, close to 10kv High-voltage Line and construction power transformer in the east of the foundation pit, complex foundation pit soil layer, narrow construction site, multi position and multi type of work with three-dimensional cross operation, tight construction period, difficult construction technology, complex surrounding environment and large safety variables; The safety management is difficult, and the safety management disclosure is formulated according to the characteristics of the project
. 
The lower earthwork can be excavated only after the foundation pit support structure reaches the strength required by the design
.
Whether detailed safety technical disclosure is made to the operation team and workers; Check the disclosure records and ask relevant personnel
. 
preparation basis: Standard for safety inspection of building construction (jgj59-2011)《 Technical code for safety of temporary electricity on construction site (JGJ46-2005)《 Technical code for safety of fastener type golden steel pipe fastener scaffold in building construction (jgj130-2011)《 Technical code for safety of work at heights (jgj80-2016)《 Technical code for safety of Deep Foundation Pit Engineering (jgj-311-2013)《 Technical specification for building foundation pit support jcj120 technical code for safety of earthwork engineering in building construction jgj180 II
. 
4
.
2
.
Whether the supporting structure has been accepted as required and meets the specifications and design requirements; Check whether the indoor acceptance data of the support structure are complete
. 
Check the quality of support structure
. 
During the use of deep foundation pit, the foundation pit and surrounding environment shall be inspected regularly to check the displacement (soil crack), inclination of foundation pit, settlement or uplift of soil and surrounding roads, groundwater gushing, pipeline cracking, emission of unknown gas and the safety of foundation pit protective railing
.
Check the safety of construction electricity
. 
The erection of stairway shall meet the requirements of relevant safety specifications
.
Therefore, it bears the greatest safety risk, and safety management has become the primary task（ 1） 1
. 
Waterproof lamps shall be used on the construction site
. 
7.2 whether the emergency plan measures have been implemented; Check the preparation of on-site materials, machines and tools
.
Emergency plan shall be prepared for foundation pit works
.
Check pit side load
. 
Whether the wall protection quality inspection has been carried out (such as pile integrity inspection); Check the test results
.
Check the site earthwork excavation
.
Attention should be paid to the construction of foundation pit support structure: (1) whether the depth and quality of pile can meet the design requirements
.
Check whether the safety management measures are implemented during the use of deep foundation pit
.
