To tackle the challenge of dislocation damage when tunnels traverse active fault zones, this study introduces the concept of using brittle buffer materials for anti-dislocation. Building on this concept, we propose a novel concrete buffer material utilizing large-sized spherical super absorbent polymers (SAP) as a porogen, aimed at ensuring the safety of tunnel structures during active fault dislocations. To investigate the feasibility and superiority of SAP concrete as a buffer material compared to other similar materials, we prepared samples with three different SAP concrete proportions and conducted a series of physical and mechanical tests. The results show that SAP pre-hydrated with 0.2 mol·L−1 sodium carbonate solution exhibits a slower rate of moisture loss in the cement slurry, aiding the hydration reaction of concrete. The permeability coefficient of SAP concrete is approximately 10−7 cm·s−1, slightly lower than foam concrete of the same density level. SAP concrete buffer material demonstrates significant brittleness, in contrast to the mostly ductile nature of other buffers such as foam concrete and rubberized concrete. Utilizing the brittle nature of SAP concrete materials, when applied to tunnels affected by stick–slip active fault dislocations, its instantaneous loss of compressive capacity provides excellent yield performance, thus protecting the tunnel lining from damage. However, under certain circumferential pressure conditions, both the peak and residual strength of SAP concrete significantly increase. High peak and residual strengths do not favor the effective buffering effect of SAP concrete; therefore, an approach involving the intermittent arrangement of precast buffer blocks has been proposed for application.

中文翻译：

---

活动断裂带隧道缓冲层设计SAP混凝土力学试验及工程适用性分析

为了应对隧道穿越活动断裂带时的位错损伤挑战，本研究引入了使用脆性缓冲材料进行抗位错的概念。基于这一概念，我们提出了一种新型混凝土缓冲材料，利用大尺寸球形高吸水性聚合物（SAP）作为致孔剂，旨在确保活动断层位错期间隧道结构的安全。为了研究 SAP 混凝土作为缓冲材料与其他类似材料相比的可行性和优越性，我们制备了三种不同 SAP 混凝土比例的样品，并进行了一系列物理和力学测试。结果表明，0.2 mol·L SAP 预水化−1碳酸钠溶液在水泥浆中的水分损失速度较慢，有助于混凝土的水化反应。 SAP混凝土的渗透系数约为10−7厘米·秒−1，略低于同密度级别的泡沫混凝土。 SAP 混凝土缓冲材料表现出明显的脆性，而其他缓冲材料（例如泡沫混凝土和橡胶混凝土）大多具有延展性。利用SAP混凝土材料的脆性特性，当应用于受粘滑活动断层位错影响的隧道时，其抗压能力的瞬时丧失提供了优异的屈服性能，从而保护隧道衬砌免受损坏。然而，在一定的周向压力条件下，SAP混凝土的峰值强度和残余强度均显着增加。高峰值强度和残余强度不利于SAP混凝土的有效缓冲作用；因此，一种涉及预制缓冲块间歇布置的方法被提出并应用。