鹧鸪山特长公路隧道通风平导新型中隔墙技术可行性研究

特长公路隧道的通风平导采用混凝土中隔墙会导致施工进度缓慢且通风阻力增大,针对这一弊端,提出钢波纹板代替混凝土的新型中隔墙技术。通过数值模拟,从通风性能、力学性能、耐火性能等方面对新技术进行可行性分析,同时对其耐久性、密封性等其他性能进行研究。结果表明: 1)采用新型中隔墙会因风道断面面积增大而导致断面风速略有降低(约4%),但不影响通风效果; 2)平导拱顶沉降增至3. 783 mm,且固定柱轴力为124. 576 kN,未影响结构安全; 3)主洞发生火灾时平导内烟流未出现回流,且最高温度(168 ℃)未超过钢板正常使用范围; 4) 钢波纹板的耐久性、密封性等均满足要求; 5)新型中隔墙技术在保证施工进度的同时也满足特长公路隧道的通风防灾要求。

Study of New Intermediate Diaphragm Wall in Ventilation Parallel Heading of Zhegushan Extra-long Highway Tunnel

The problems of slow construction speed and ventilation resistance increase caused by intermediate diaphragm wall made of concrete in parallel heading of extra-long highway tunnel should be solved. As a result, a new intermediate diaphragm wall in which the concrete is replaced by steel corrugated plate is proposed. And then the feasibility of the technology is analyzed by numerical simulation from the aspects of ventilation performance, mechanical performance, and fire-resistance performance. Finally, the properties of the wall such as durability and sealing are studied. The results show that: (1) The new intermediate diaphragm wall will cause the increase of cross-section area of ventilation parallel heading, which results in a slight decrease in the cross-section wind speed (about 4%), but it will not affect the ventilation effect. (2) The crown settlement of the parallel heading increases to 3. 783 mm, and the axial force of fixed column reaches 124. 576 kN, which indicates no influence on structural safety. (3) The smoke flow in the parallel heading does not return when fire occurs in the main tunnel, and the maximum temperature (168 ℃) does not exceed the normal range. (4) The durability and sealing performances of the steel corrugated plate also meet relevant requirements. (5) The new technology can meet the ventilation and disaster prevention requirements of extra-long highway tunnels and ensure the construction speed.