【摘要】：我國(guó)現(xiàn)存有大量歷史悠久的木結(jié)構(gòu)古建筑,她們具有極其重要的歷史文物價(jià)值,將其久遠(yuǎn)傳承是一項(xiàng)艱巨任務(wù)。由于結(jié)構(gòu)所用木材的易燃性,使得大量宏偉木結(jié)構(gòu)古建筑在火災(zāi)中消失或毀壞,如著名的阿房宮、圓明園等。在對(duì)非嚴(yán)重?zé)龤У墓沤ㄖM(jìn)行修復(fù)加固時(shí),考慮到古建筑須遵循“不改變文物原狀、修舊如舊”的修復(fù)原則,通常對(duì)受火災(zāi)影響較輕的木構(gòu)件繼續(xù)使用,而此時(shí)木材經(jīng)火災(zāi)的高溫后其物理力學(xué)性能將發(fā)生顯著變化,因此掌握高溫后木材的各項(xiàng)物理力學(xué)性能顯得尤為重要。本文以我國(guó)古建筑木結(jié)構(gòu)常用樹種落葉松為研究對(duì)象,通過試驗(yàn)研究了高溫后落葉松材的主要物理力學(xué)性能及溫度、恒溫時(shí)間、降溫方式對(duì)其物理力學(xué)性能的影響規(guī)律。主要研究結(jié)論如下:(1)高溫對(duì)木材的含水率、失重率及外觀顏色均有很大影響。隨著溫度的升高和恒溫時(shí)間的延長(zhǎng),木材的含水率呈降低趨勢(shì);木材的質(zhì)量損失呈遞增現(xiàn)象;木材外觀顏色由淺褐色逐漸變?yōu)樯詈稚?其中200℃-250℃是木材顏色顯著變化的溫度區(qū)段。(2)高溫后木材的各項(xiàng)力學(xué)性能[順紋抗壓強(qiáng)度、順紋抗壓彈性模量、順紋抗拉強(qiáng)度、順紋抗剪強(qiáng)度(弦面)、橫紋抗壓強(qiáng)度(全表面,徑向)、橫紋抗壓彈性模量(徑向)]均有不同程度降低,降低程度受溫度、恒溫時(shí)間和降溫方式的影響,其中溫度是最主要的影響因素。(3)在試驗(yàn)研究的基礎(chǔ)上建立了高溫后木材順紋抗拉本構(gòu)方程、順紋抗壓本構(gòu)方程、橫紋抗壓本構(gòu)方程。
[Abstract]:There are a large number of ancient wooden structures with a long history in our country, they have extremely important historical relics value, it is a difficult task to inherit them for a long time. Because of the flammability of the wood used in the structure, a large number of magnificent wooden structures disappeared or destroyed in the fire, such as the famous A Fang Gong, Old Summer Palace and so on. Taking into account the principle of "no change in the original state of cultural relics, repair as old", taking into account the principle of "no change in the original state of cultural relics," in the restoration and reinforcement of ancient buildings that are not severely burned, and generally continue to use wood elements that are less affected by fire, At this time, the physical and mechanical properties of wood will change significantly after the fire, so it is very important to master the physical and mechanical properties of wood after high temperature. In this paper, the main physical and mechanical properties of larch timber after high temperature and the influence of temperature, time of constant temperature and cooling mode on its physical and mechanical properties were studied. The main conclusions are as follows: (1) High temperature has great influence on wood moisture content, weight loss rate and appearance color. With the increase of temperature and the prolongation of the time of constant temperature, the moisture content of wood decreased and the loss of wood mass increased. The appearance color of wood gradually changed from light brown to dark brown, in which 200 鈩，

本文編號(hào)：2364988