The first construction site of the second phase of guangzhou metro line 7 was completed

Recently, the bottom plate of the middle air shaft from the south of the second phase university of line 7 to the deep shaft (hereinafter referred to as "deep shaft") was poured successfully, becoming the first work site on the whole line to complete the bottom sealing of the foundation pit.

According to the introduction, the second phase of line 7 has a total length of 21.9 kilometers, starting from the south station of the first phase of the university city and extending to the north of the water northwest station. All underground laying is adopted, with a total of 11 stations and one shangtang parking lot (all of which are tentative names of the project).

Introduction of ultrasonic real-time detection of construction safety

The wind shaft in the second phase of the great deep section of line 7 is 47 meters long, 28 meters wide and 30.7 meters deep. It is an underground four-story structure. Metro group is introduced, and the middle complicated regional geological conditions of the wind well is a construction in the process of a big "obstacle", encountered in the construction of soft layers (i.e. the upper is muddy silty sand, middle sand clayey soil, the lower is composed of weathered granite and strongly weathered granite formation), in the silt layer construction easy to continuous wall tank wall collapsed.

For this reason, the subway builders discussed the mud proportioning scheme in advance, and made the mud wall protection in the process of tank formation by adjusting the mud proportioning index. In view of the complex geological conditions, the traditional detection method is difficult to accurately reflect the construction situation, specially introduced the ultrasonic detector, through the ultrasonic data information to understand the enclosure structure into the groove situation, to ensure the construction quality and safety of the middle air shaft.

In the construction process, subway builders also introduced fog cannon, sprinkler system, mud press filter and car wash tank and other equipment, through real-time monitoring of the site surrounding environmental index, purification of sewage, control dust, promote green and civilized construction.

Water storage and heat preservation ensure the quality of concrete casting

According to the introduction, the sealing of the middle wind shaft with shield well function, will undertake the interval tunnel four (secondary) shield machine initial task. The amount of concrete pouring at the bottom of the pit is about 1917 cubic meters. In order to prevent the high hydration heat of mass concrete during the pouring process and the risk of temperature variation cracks, the subway builders optimized the concrete mix ratio and ensured the quality of concrete pouring by means of water storage and heat preservation.

Up to now, the civil engineering of the second phase of line 7 has been completed by 4%. Of the 11 stations, 8 are under civil construction, and the remaining 3 are in preparation. Of the 11 sections, 4 started civil construction, and the remaining 7 were prepared.