【作者】 马海春；

【导师】 顾金才； 李永池；

【作者基本信息】 中国科学技术大学 ， 工程力学， 2011， 博士

【摘要】 随着科学技术的发展,高尖端武器可以高精度命中目标,钻地深度越来越深,爆炸强度越来越强,对地下各种防护工程结构造成了巨大的威胁。为了提高防护工程地下结构以及周围岩体对钻地武器爆炸的抗破坏能力,本文通过锚固洞室现场抗爆能力实验,数值分析和锚杆锚固性能研究,希望能够为地下结构体系的安全性问题提供一些参考,本文主要研究结果有一下几个方面:1.对比现场多炮次各种锚杆锚固洞室抗爆炸的实验,主要包括:短密锚杆支护类型;长密锚杆支护类型;常规锚杆支护类型以及网喷支护类型。从宏观破坏的现象来看,出现了洞室顶部混凝土喷层脱落或者开裂,两侧的拱脚附近会出现剪切错动裂缝,洞室顶部和拱脚位置是受爆炸影响比较严重的位置。特别在常规锚杆支护的条件下出现多根锚杆外端和垫板外混凝土喷层震落,并且从混凝土喷层开裂程度和锚杆垫板外震落的混凝土块大小、深度上看,长密锚杆段比短密锚杆段破坏程度更为严重,长密锚杆段局部钢筋网已经外露。2.对比分析了洞室顶部的竖向位移,以及相对于比例距离的关系,得到了顶部的竖向位移与跨度的比值随着各炮次的比例距离的增大而呈负指数性衰减。各位移波形规律性很好,都有一个向下的最大位移峰值和一个较小的向回弹跳的较小峰值,然后是残余位移。从最大峰值位移所对应的时间看,常规锚杆为43到47ms左右,短密锚杆和长密锚杆为39到40ms左右。从顶部的位移来看,长密锚杆支护的洞室顶部竖向位移比短密锚杆支护的洞顶竖向位移要大,说明在本实验条件下,锚杆的支护效果不一定是锚杆越长越好。分析了各炮次爆炸作用下锚杆的应变特征,得到锚杆应变的波形形式。在本实验中,对比了各个位置和不同支护类型的锚杆的应变特征,锚杆应变主要是压缩的,相对而言长密锚杆支护类型的锚杆应变比短密锚杆和常规锚杆支护的条件下锚杆的最大应变要大。本文给出了各个位置锚杆峰值的包络线,发现各个锚杆最大应变位置的情况不同。网筋的应变有着相同规律性波形。网筋的应变有拉有压,情况不一。对于各个位置加速度的分析,因位置不同,规律性表现不同,顶部位置规律性较好。加速度峰值与比例距离的关系也有指数衰减的关系。3.利用数值分析软件分析了第五炮作用下的三种锚杆锚固形式的洞室顶部竖向位移,洞室的破坏情况,锚杆的应力应变情况。从结果上看,破坏区依然是在洞顶和拱部比较严重。从锚杆支护效果上来分析,长密锚杆支护效果比短密锚杆支护的效果也略差,这与实验结果是一致的。另外,对围岩强度和爆炸比例距离对洞室顶部竖向位移的影响作了分析。4.对锚杆锚固性能做了些研究。结合理论模型分析了锚杆体系在周围岩石粘弹性作用下的应力波的传播情况,以及喷层交界面的透反射情况。更多还原

【Abstract】 As science and technology develop, hi-tech weapons can attack aims in high precision. The depth that weapons penetrate in land gets deeper and deeper. The explosion strength gets stronger and stronger. So the underground protective structures face tremendous threat. To improve the explosion resisting capacity of protective structures and surrounding rock when the land-penetrating weapons explode, this passage may supply some references to the safety problem of underground engineering projects through the research for the site explosion resisting capacity tests of underground cavern reinforced by grouted rockbolts; through the numerical analyse; and through theoretic research of rockbolts. Some conclusions are brought as follow:1. The explosion resisting capacity site tests of underground cavern reinforced by grouted rockbolts include: short and close rockbolts; long and close rockbolts; regular rockbolts; and grout sprayed. From the macroscopic destroyed appearances, the sprayed grout are cast and crazed. Some sheared crevices appear at the arch of carven. The positions at the top and arch are easily to be destroyed. Especially some grout at the ends of some rockbolts ruined more heavily for the long and short rockbolts type than for the short and short rockbolts type. It indicates that the destroyed situation for the long and short rockbolts is more serious.2. Comparing the displacements at the top of caverns and the relationships between the displacement peak values and the relative explosion distances, the ratio that the displacement peak values divided by the span decayed in negative index law. Every displacement wave has a simple regularity. It goes down to a bottom that is the maximal displacement, then it reboundes to a smaller displacement, at last the wave verges to placidity. For the time that the wave reaches maximal displacement, it is between 43 ms and 47 ms for regular rockbolts type, and it is about 39 ms or 40 ms for short and close rockbolts type or long and close rockbolts type. For the displacements at the top of caverns, the vertical displacement peak value for long and close rockbolts type is higher than for short and close rockbolts type. It suggests that the length of rockbolts may not support caverns to resisting explosion. The strain waves of every rockbolt are also brought out and analysed. The rockbolts are mainly subjected to compression. The strain value for long and close rockbolts type is higher than for short and close rockbolts. This passage also introduces rockbolts strain peak value enveloping line and the maximal strain does not appear at same position for every rockbolt. The strain of rebar has analogous regularity. The strain is not only tension but also compression. For analyse of acceleration at different positions, the regularities are different. The acceleration peak value decreases in negative index law.3. Making use of numerical analysing software, the vertical displacements at the top of three kinds of caverns in different protective conditions are analysed. And the strain situations of the caverns and rockblolts are also researched. The destroyed situations at top and arch of caverns are still severe. And also the short and close rockbolts have a better protective effect than the long and close rockbolts. The conclusions are same as the site tests. In addition, the influences of the rock elastic modulus to the displacement at the top of cavern are analysed. And the influences of explosion relative distance to the displacement at the top of cavern are analysed, too.4. Some researching jobs about rockbolts’ effects are put forward. A viscoelastic model of rockbolt thinking of surrounding rock effects is analysed. The stress wave propagation situation is researched and stress wave’s transmission and reflection situation at the position of prayed grout is brought out.更多还原