Continuous tunneling using a tunnel-boring machine is a very popular method when it comes to the construction of large tunnel projects. The use of precast reinforced concrete elements, called tubbings, is a highly economical way to secure the tunnel post excavation. Unfortunately, a loss of the load-bearing capacity has been observed in the past in the joints between the tubbings. Reasons for that are among others the required reduction of the cross section in the longitudinal joint area and, above all, the high normal compressive forces that arise due to soil pressure. This paper describes experimental testing of longitudinal joints of tubbings conducted at TU Wien. The increase of the load-bearing capacity of a newly designed and optimized tubbing with high-strength joint-compressive reinforcement, which was developed and patented by the Institute of Structural Engineering at TU Wien, is presented. The high-strength steel is characterized by its high yield strength of 670 MPa, as well as the very large available bar diameters of up to 75 mm. This new optimized tubbing enables the production of thinner tubbings compared to conventional designs, and can thus achieve a reduction in material, transport and excavation costs.

中文翻译：

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新设计的高强度加强管的纵向接头

在大型隧道项目的建设中，使用隧道掘进机进行连续隧道掘进是一种非常流行的方法。使用预制钢筋混凝土构件（称为管筒）是一种非常经济的方式来保护隧道开挖后的安全。不幸的是，过去曾观察到管子之间的接头失去了承载能力。造成这种情况的原因之一是需要减少纵向接头区域的横截面，尤其是由于土壤压力而产生的高法向压缩力。本文描述了在 TU Wien 进行的管道纵向接头的实验测试。新设计和优化的高强度接缝抗压加强管的承载能力增加，展示了由 TU Wien 的结构工程研究所开发并获得专利的产品。这种高强度钢的特点是其屈服强度高达 670 兆帕，以及可用的钢筋直径高达 75 毫米。与传统设计相比，这种经过优化的新管道能够生产更薄的管道，从而降低材料、运输和挖掘成本。