KVALITETA ZRAKA I MIKROKLIMATSKI PARAMETRI PRI ISKOPU TUNELA MALA KAPELA

Mario Klanfar, Darko Vrkljan, Miroslav Lončarić
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引用次数: 1

Abstract

During excavation of the Mala Kapela tunnel, measurements of harmful gases concentration, ventilation parameters and microclimatic parameters were performed. Measurements were done in 17 occasions during period of 16 months, along the advance of the tunnel excavation. Consequently, large amount of data was obtained, in different tunnel chainages, ventilation ducts length, and in different work operations during the excavation. Main sources of harmful gases during tunnel excavation are explosives and diesel equipment. The concentration of the same mainly depends on explosive charge and overall diesel equipment power, present at the excavation face of the tunnel. Continuous measurements of the concentration of carbon monoxide (CO) and dioxide (CO2), and nitrogen oxide (NO) and dioxide (NO2) was performed during drilling, blasting, and loading and haulage operations. Measurements were done in 45 cases in total. Recorded data was analysed, where peak concentrations were joined to corresponding operation and the tunnel chainage. Regulations on threshold limit values were used to determine if concentrations rise above the permissible ones. In case they do, the time required for dilution of gases below permissible concentration was noted. Typically, concentrations of all measured gases rise rapidly after blasting. Afterwards, ventilation system acts to dilute them and maintain them relatively constant until the end of loading and haulage. According to measurements in this research, highest concentrations and longest time of dilution were found after blasting. At the same time, concentration of all measured gases exceeds permissible values. Carbon monoxide is found to exceed permissible values during all work operations. It shows most frequent transgression above the limit (in 33 to 100% of cases) and highest time of dilution (up to 40 min). Air supply to the excavation face was measured in 25 cases. It was correlated to the length of ventilation ducts, as the tunnel excavation advances. Results show the trend of air flow drop of 0,3 to 1,2 m3/s per 100m of duct length, with average value of 0,7 m3/s. In accordance with air flow drop, higher peak concentrations and longer time of dilution was observed for drilling and blasting operations. Conversely, lower concentrations and shorter time of dilution were found for loading and haulage operation. This could be attributed to longer truck cycle as excavation advances, thus less diesel units are present in proximity of the excavation face. Measured data on microclimatic parameters was correlated to season changes, distance form tunnel entrance and mutually. Air temperature was measured in 8 cases, along the tunnel and outside in the proximity of the entrance. Recorded data shows that temperature is constant along the tunnel. That is, there is no change with depth of the tunnel below surface, which is up to 433m. It was found that temperature mainly depends upon season and upon outer air that is supplied by ventilation to the tunnel. Highest temperature was recorded during summer (20 to 27 °C), when inner and other temperature are in approximate equilibrium. Lowest inner temperature was recorded during winter (12 to 17 °C), when difference from outer temperature rises. Relative humidity was measured in 14 cases. Recorded data shows random character, so no relations were derived, except that inner air is more humid on average and it's humidity varies much less compared to the outer air. Outer humidity ranges between 36 and 99%. Inner humidity ranges between 53,6 and 99,3 %, and it was 11,8% higher on average. Air pressure was measured in 15 cases. It was found that it corresponds to the outer atmospheric pressure. There is normal pressure drop with distance from tunnel entrance, as vertical alignment of the tunnel changes it's altitude.
在Mala Kapela隧道开挖过程中,进行了有害气体浓度、通风参数和小气候参数的测量。在16个月的时间里,沿着隧道开挖的进度进行了17次测量。因此,在开挖过程中,在不同的隧道链、通风管道长度和不同的作业方式下,获得了大量的数据。隧道开挖过程中有害气体的主要来源是炸药和柴油设备。其浓度主要取决于存在于巷道开挖面上的炸药装药量和整体柴油设备功率。在钻井、爆破、装载和运输过程中,连续测量一氧化碳(CO)和二氧化碳(CO2)以及氮氧化物(NO)和二氧化氮(NO2)的浓度。总共测量了45例。对记录的数据进行分析,将峰值浓度与相应的操作和隧道链相结合。有关阈值的规定用于确定浓度是否超过允许的水平。在这种情况下,要注意将气体稀释到允许浓度以下所需的时间。通常,爆破后所有被测气体的浓度迅速上升。然后,通风系统将其稀释并保持相对恒定,直到装载和运输结束。根据本研究的测量,爆破后的稀释浓度最高,稀释时间最长。同时,所有被测气体的浓度均超过允许值。在所有工作操作过程中,发现一氧化碳超过允许值。它显示最常见的超标(33%至100%的病例)和最长的稀释时间(最多40分钟)。测量了25例开挖工作面送风情况。随着隧道开挖的推进,它与通风管道的长度相关。结果表明:风管长度每100m风量下降幅度为0.3 ~ 1.2 m3/s,平均值为0.7 m3/s;随着空气流量下降,钻孔和爆破作业的峰值浓度更高,稀释时间更长。相反,在装载和运输操作中,稀释浓度较低,稀释时间较短。这可能是由于随着挖掘的推进,卡车周期变长,因此在挖掘工作面附近的柴油装置较少。小气候参数实测数据与季节变化、与隧道入口的距离及相互之间存在相关性。在8个案例中测量了沿隧道和靠近入口的室外的空气温度。记录的数据表明,隧道沿线的温度是恒定的。也就是说,在地表以下隧道深度为433m时,不随深度的变化而变化。研究发现,温度主要取决于季节和隧道通风所提供的外部空气。最高温度记录在夏季(20至27°C),此时内部和其他温度接近平衡。内部温度最低记录在冬季(12至17°C),此时与外部温度的差异增大。测量了14例患者的相对湿度。有记录的数据显示出随机特征,所以没有推导出关系,除了内部空气平均更潮湿,它的湿度变化比外部空气小得多。外部湿度在36 - 99%之间。室内湿度在53.6%至99.3%之间,平均高出11.8%。测量15例患者的气压。结果发现,它与外部大气压力相对应。随着距离隧道入口的距离,由于隧道的垂直方向改变了它的高度,存在正常的压降。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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