工字钢冷弯机_支持定制

一种金属加工方法。在室温下将金属材料板、带材用机械弯曲成一定形状和尺寸的型材。其产品称为冷弯型材。冷弯的优点是：可以生产轧制不能生产的各种特薄、特宽和形状复杂的型材；节省金属材料;；制品机械性能好。常用的加工方法有辊弯、压弯、拔弯和折弯。

///

常温下将金属板带材经弯曲变形制成型材 （或零件）和焊管管筒 （见辊式成形）的金属塑性加工方法。广义的冷弯变形包括折弯、辊模弯曲、三辊弯板、连续辊轧弯曲等。由于连续辊弯成形所生产的型材和焊管管筒产量大，产品定型，因此狭义的冷弯变形就是指这一种特定的弯曲变形。其产品称为冷弯型材，半成品即焊接管管筒。

///

冷弯型材的*一次公开报导是1855年美国纽约修建办公大楼时用了铆接工字梁。连续辊弯成型机组1910年始建于美国，此后冷弯型材生产则大力发展起来。与热轧型材比，冷弯型材尺寸精*、外表光洁、具有热轧无法生产的异形断面形状、相同重量下抗弯和抗扭性能好，因而使用冷弯型材能节约金属百分之三十*上。此外生产方式简单，设备投资不大。故冷弯型材生产不断得到发展。一般先*产钢冷弯型材占轧材总量的2%～4% （*高达5%）。

///

冷弯型材用原料：常用的是低碳钢、铝、铜等板带材，此外还有不锈钢、钛金属、复合金属的板带。碳钢板带厚度为0.15～3.2mm，热轧板带厚度为1.2～25.4mm。铝板带厚度为0.13～25.4mm。据报道，不少已能生产厚达32mm的冷弯型钢。原料宽度根据成品的断面展开长度确定，由纵剪机剪成板带材进入成型机组，由一对相对转动的成形辊依次弯曲成所要求的成品形状，如图1所示；板料的成形过程。

///

分为从单张板材弯成单件型材的单张生产方式、以整卷带材为原料生产型材的成卷生产方式和以卷材为原料并将其头尾对焊在一起的连续生产方式等3种。连续生产方式由于产品尺寸精度好、生产率高而得到更多的发展。连续冷弯型钢的典型设备组成及布置如图3所示。无论哪种生产方式，其整个工艺过程均分为原料准备、成形和精整3个阶段。

一般开式冷弯型材工艺流程为：带钢卷→纵剪→上料→开卷→矫直→切头→对焊→储料器储料→成形→矫直→切断→检查收集→打捆→称重→入库。

闭式冷弯型材工艺流程为：带钢卷→纵剪→上料→开卷→矫直→切头→对焊→储料器储料→成形→高频焊接→除毛刺→冷却→矫直→切断→检查收集→打捆→称重→入库。

如在生产线上增加冲孔、压痕、扭弯等附加工序，就可生产出各种异形冷弯型材。

隧道支护结构体系是围岩稳定性控制的关键,也是隧道设计的基本任务,而对支护结构之间相互作用过程和机制的系统认识则是定量化设计的基础. 本文从隧道围岩结构性和支护作用的本质特征出发,提出隧道支护具有"调动"和"协助"围岩承载的基本作用,明确了二者的功能分配原则和实现方式,即分别通过超前支护的保障作用、初期支护的核心作用和二次衬砌的储备作用共同完成;针对围岩的正面挤出、前倾式冒落和后倾式冒落等三种超前破坏模式,分别给出了相应的超前支护方式和支护效果评价方法;提出初期支护作为隧道围岩附加载荷的主要承担者,包括锚固体系与拱架及喷射混凝土结构,分别通过"调动"和"协助"围岩实现其承载功能,且同时具有"支"与"护"的作用;阐明了二次衬砌结构作为储备功能的内涵,建立了二次衬砌结构的载荷分担比率与刚度匹配性、支护时机的关系,并据此给出了二次衬砌结构参数和施作时机的建议值;建立了以围岩变形量$S$小和协同度$\xi$优为目标,基于超前支护、初期支护和二次衬砌与围岩相互作用三阶段的协同支护优化模型,明确了支护结构体系与围岩、不同支护结构之间以及支护结构要素之间三个层次的协同关系,并提出了隧道支护结构体系协同优化设计方法.

关键词: 隧道工程, 支护结构体系, "支护——围岩"动态作用, 协同作用, 支护结构设计

Abstract:

Tunnel support structure system is the key of controlling the stability of surrounding rock, which is also the basic task of tunnel design, while systemic understanding of the process and mechanism of interaction among support structures is the basis of quantitative design. This paper embarks from structural property of tunnel surrounding rock and the constitutive property of support effect, the basic function of tunnel support that "mobilizing" and "assisting" surrounding rock bearing is put forward, of which the function distribution principle and realization way are clarified, namely, through the guarantee role of advanced support, the core role of primary support and safety reserve role of secondary lining to complete. In view of three advanced failure modes including the positive extrusion, the forward type caving and posterior tilt falling of surrounding rock, the corresponding advanced support pattern and its effect evaluation method are given respectively. The primary support is the main undertaker of tunnel surrounding rock additional load, including the anchorage system and the arch and shotcrete structure, whose bearing function is carried out by "mobilizing" and "assisting" surrounding rock respectively, and also have the function of "bracing" and "protecting". The connotation of secondary lining structure as security reserve function is illuminated. The relationship between load sharing ratio and stiffness matching and support time of secondary lining structure is established, according to which the suggestive values of structure parameters and support time of secondary lining are provided. The collaborative support optimization model is set up based on the three stages of the interaction between advanced support, primary support, secondary lining and surrounding rock, whose targets are minimizing surrounding rock deformation S and optimizing synergy degreeξ. Three levels of synergy including relations between support structure system and surrounding rock, different support structures and different support structure elements are clarified. And a collaborative optimization design method for tunnel support structure is proposed.