On the 14th, cut-and-cover construction will begin at the Ma'anshan Road intersection of the Phase II underground road project of the Shunhe Elevated Road South Extension. The inclined shafts at Ma'anshan Park and Shunyu Road were excavated 10 days ago. Tunnel construction is now in full swing. Although digging tunnels is no longer a big deal in Jinan, and many civil air defense projects in the city have also involved tunnel excavation, the reporter still learned the latest construction arrangement details from the Shunhe Elevated Road South Extension Project Department. In order to complete the tunnel as soon as possible and reduce the impact on nearby residents, the contractor has specially arranged for mechanical non-blasting excavation. Moreover, during underground excavation, construction will be carried out simultaneously in two levels, upper and lower, which indeed sounds quite advanced.
        On Yuhan Road, from 80 meters south of the Yuhan Interchange south ramp to the Niuzhen BBQ not far south of the Ma'anshan Road intersection, fully enclosed barriers will be set up to begin construction of the future connection between the Shunhe Elevated Road and the tunnel. This section will be a cutting.
        Previously, seedling relocation, utility relocation, and construction access roads on both sides had been carried out. After cut-and-cover begins, the approximately 3-kilometer-long main tunnel between the inclined shaft at Ma'anshan Road intersection and the inclined shaft at Qilishan Road on Yuhan Road will be fully launched with bidirectional advancement. With excavation at both the Ma'anshan Road and Qilishan Road intersections, and two additional inclined shafts at Ma'anshan Mountain Park and Shunyu Road intersection in between, three construction sections and five working faces will be excavated simultaneously to maximize excavation speed.
       During tunnel excavation, the sequence will be inclined shafts first, then cross passages, and finally the main tunnel. After the inclined shafts are connected to the main tunnel area, the "three-into-two" center drift method will be used for tunnel excavation. First, reserve the cross-sections of about three tunnels, then excavate the center tunnel first. After about 50 meters of excavation, build a concrete partition wall in the middle and simultaneously support the entire tunnel face.
        A single tunnel face will be constructed using the benching method. After the upper bench is excavated, temporary support will be installed immediately, and then the lower bench excavation will proceed, carrying out double-layer operations to improve construction progress.
       To ensure the safety of surrounding buildings, the underground tunnel will be located 8 meters below the existing road. Moreover, the entire Phase II project will mostly use cantilever roadheaders for non-blasting excavation, and dynamic monitoring of the ground road and buildings on both sides will be implemented during construction to maximize the safety of the entire project and surrounding buildings.
       The cantilever roadheader consists of a dust suppression spray system and a cutting mechanism. While cutting and excavating, water spray suppresses dust, avoiding the large impact of blasting, causing little damage to the surrounding rock, with almost no loosening or falling blocks, and minimal risk of collapse. During construction, vibration and noise are low, with little impact on nearby residents and structures, greatly improving safety and the working environment.
       During underground tunnel excavation, ground road vehicles can pass normally, avoiding the adverse effects of full traffic closure caused by cut-and-cover construction. After construction is completed, both the existing ground road and the underground road can be used simultaneously, achieving a fast connection between the Shunhe Elevated Road and the Second Ring South Road Expressway.
       In addition, a water curtain dust removal system will be installed. At the tunnel face, the secondary lining trolley, and the inclined shafts, fully enclosed green construction sheds will be built, and fully enclosed muck transport will be carried out to ensure the construction environment inside and outside the tunnel and the health and safety of workers.
       Dust inside the shed can only escape through the muck storage bin and the sand and gravel material bin doors. A water mist spray system will be installed along the upper edge of the doors, to be activated during the transfer of muck and sand/gravel to reduce dust and pollution. Vehicle washing facilities will be set up at the exits.
       In addition, the Phase I project of the Shunhe Elevated Road South Extension has completed more than 140 piles, over half of the total; the first batch of piers has begun bracket installation, with pouring scheduled to start on the 15th, and box girder pouring will begin in June.