共查询到20条相似文献，搜索用时 464 毫秒
1.
《佳木斯教育学院学报》2019,(6)
本篇文章首先对浅埋暗挖法隧道施工的施工原理进行概述,从开挖方法、隧道支护、辅助施工三个方面,对浅埋深挖施工技术进行解析,并结合浅埋暗挖隧道施工造成地表沉降的影响因素,提出浅埋暗挖法隧道施工地面沉降控制措施。 相似文献
2.
随着开采深度增加,回采巷道锚杆支护的难度越来越大,该文基于薛湖煤矿29020机巷围岩赋存地质条件,实验室测试了巷道围岩物理力学参数,现场实测了巷道围岩松动圈,提出了锚固应力叠加控制原理。在此基础上进行了锚杆支护参数的理论计算,并采用数值模拟优化了锚网索支护参数,在薛湖煤矿29020机巷进行了现场应用,取得了较好的技术经济效益。研究结果表明：29020机巷顶板存在80～100cm的松动圈;采用“锚杆+短锚索+长锚索”多层支护形式可更好地保证围岩稳定性,并计算得到锚杆合理长度为2.4 m,间排距为0.7 m×0.8 m,长锚索8.3 m,短锚索5.5 m,间排距为1.4 m×3.2 m;巷道顶板、两帮位移量10～20 mm,锚杆、短锚索、长锚索端锚力分别为50～100 kN、100～150 kN、100～200 kN,29020机巷围岩稳定性得到了较好控制。 相似文献
3.
通过在同家梁矿14#层311盘区51013巷与311-1巷交汇处架设20#工字钢钢架做交叉点对顶板进行加强支护,保证了上覆煤柱下巷道支护的稳定性,促进了矿井的安全生产,对类似顶板条件的巷道支护技术具有一定的借鉴意义。 相似文献
4.
文章介绍了套孔应力解除法进行地应力测试的方法，并应用此法对盛平煤业有限公司-630m水平采区进行了地应力现场实测，根据5个地应力测站现场实测数据，得出了主应力与埋深、侧压比之间的关系，判定了应力量级，分析了背斜对地应力的影响。利用地应力分布特征对巷道布置方向及巷道两帮支护参数设计进行指导，确保了巷道稳定性，保障了安全生产，可为类似条件下矿井的安全开采提供参考。 相似文献
5.
为研究弱胶结砂岩巷道在开采过程中的变形特征,解决巷道围岩发生严重破坏、围岩稳定性较差、支护比较困难等问题,本文以内蒙古唐家会煤矿61101工作面回风顺槽为研究背景,通过FLAC3D数值模拟对原始支护方式进行分析,并针对原始支护参数进行优化,最终采用锚杆、锚索、W钢带和金属锚网混合支护。最终通过现场实践考察,对围岩顶板两帮变形量、锚杆索锚固力的大小进行监测,确定优化支护方案比较合理。本文认为此方法对改善此类巷道的支护有很好的效果,有利于保障煤矿安全高效生产。 相似文献
6.
锚索支护在沿空留巷中的应用 总被引：1，自引：0，他引：1
沿空留巷具有回收率高、巷道掘进率低的优点,但巷道维护难度大,合理的支护方式相当重要.锚梁网组合拱加固支护,锚索补强,则扩大了加固范围,提高了围岩的承载能力,有效地控制了顶板变形,这是沿空留巷比较理想的支护方式. 相似文献
7.
朱乐章 《淮南职业技术学院学报》2004,4(1):22-24
朱庄煤矿巷道主要支护形式有砌碹、架棚、锚喷等。由于该矿是一个已开采了40多年的老矿井且进入到深水平开采，地应力增大，地质条件复杂，巷道修复工作量大且支护效果不甚理想。锚注支护是一种主动支护，能防止围岩风化，使围岩形成一个整体，提高支护结构的完整性，扩大支护结构的适应性。锚注支护施工简单，操作性强。朱庄矿引进锚注技术，巷修工作效果显著。 相似文献
8.
厦门翔安隧道是目前世界上断面最大的海底隧道,其陆域段埋深极浅,有众多地表构造物,施工中采用双侧壁法,加强超前支护,根据洞内外监控量测结果及时调整施工,使隧道顺利安全地渡过陆域浅埋段. 相似文献
9.
米子朋 《石家庄铁路职业技术学院学报》2018,(2)
周山隧道为双向六车道分离式结构型式,最大埋深70 m。隧道工程区为黄土地层,隧道出口段70m范围埋深在5-18m,属超浅埋黄土隧道。隧道开挖跨度达16.12 m,施工过程中容易产生坍塌并波及地表。洞口段采用大管棚进行超前支护,采用双侧壁导坑法施工,及时形成封闭结构。施工效果表明,所采用施工方案能够有效控制地层变形,保证超浅埋段隧道施工安全。 相似文献
10.
针对巷道过含水软岩支护难的问题,根据煤岩体破碎机理,按照锚杆锚固约束层的作用原理,以及速凝膨胀水泥的特点,结合含水层围岩压力的特性,提出并试验了在含水软岩中采用速凝膨胀水泥网状锚杆支护方案,介绍了该锚杆的性能特点及施工工艺情况,解决了含水软岩快速固化的支护难题。 相似文献
11.
锚杆支护是一项技术上先进经济合理的巷道支扩技术,近几年来在我国煤矿得到广泛的应用。但在煤层动压卷道中使用的比例较低,其原因是煤层动压巷道的围岩变形量普遍较大,而锚杆允许的围岩变形量较小,由此提出扩大锚杆使用范围的关键措施——提高锚杆的锚固力。 相似文献
12.
信号交叉口行人相位配时方法 总被引：1，自引：0，他引：1
以信号交叉口行人相位配时为研究对象,针对信号交叉口行人和机动车对配时要求不一致以及我国行人相位清空时间不足的问题,借鉴HCM中行人绿灯最小时间和行人闪时间的计算公式,利用交通流理论,分析了行人相位和机动车相位关系,并建立了不同情况下行人信号配时方法,尤其是行人绿灯时间的调整方法.讨论了不同中央分隔带形式和宽度的行人过街方式,对计算参数的取值进行了研究,在此基础上,给出了不同情况下建议的行人配时计算模型. 相似文献
13.
梁文学 《北京工业职业技术学院学报》2007,6(1):1-4,12
应用非金属超声检测技术对孤岛工作面沿空开采巷道进行松动圈厚度测试,采集了详实的数据,总结出了松动圈厚度的变化规律,为优化支护参数提供了依据. 相似文献
14.
This longitudinal study examined the relationships among parental autonomy support, student intrinsic life goals (i.e. community feeling), student expectations for long-term educational attainment and later academic performance (measured by GPA) in 227 students in an ethnically and racially diverse high school. Hypotheses were tested with structural equation models, which included gender, parent education and prior GPA as control variables. As self-determination theory suggests, parental autonomy support was indirectly and positively related to academic performance via intrinsic life goals. Intrinsic life goals and student expectations were moderately and positively related and both contributed to growth in academic performance, which suggests that self-determination theory and expectancy-value theory provide additive insight in predicting educational achievement. Fifty per cent of the variance in intrinsic life goals was explained by parental autonomy support and 77% of the variance in later GPA was explained collectively by variables in the study. The way in which student expectations and intrinsic life goals work in concert to promote achievement should be examined in future intervention studies. The significant indirect effect of parental autonomy support on GPA via intrinsic life goals and student expectations suggests that students will benefit from parents fostering intrinsic life goals through autonomy supportive communication. 相似文献
15.
Previous research suggested that social support, belongingness and mastery goals were related to the quality of cooperative learning (CL). In this in-depth study we explored how to differentiate between four effective CL teams and four ineffective CL teams, in terms of students' goals and perceptions of instructional conditions. Apart from the earlier mentioned goals we found students' preference for social responsibility, learning for a certificate and entertainment goals to be salient in the CL setting. Mastery and social responsibility goals were prevalent in effective teams, while learning for a certificate and entertainment goals were prevalent in ineffective teams. Moreover, the type of task, group composition and teacher support were mentioned as reasons for effective or ineffective CL. 相似文献
16.
Isabelle Régner Florence Loose Florence Dumas 《European Journal of Psychology of Education - EJPE》2009,24(2):263-277
The present study examined whether students’ perceptions of two major facets of parental and teacher academic involvement
(i.e., academic support and academic monitoring), contribute to the process of students’ achievement goals adoption. French
junior high-school students completed two questionnaires assessing first their perceptions of parental and teacher academic
involvement, and then their achievement goals three months later. Factorial analyses showed that students differentiated parental
academic monitoring from parental academic support, while predominantly perceiving their teacher academic involvement as reflecting
monitoring. Multilevel modeling analyses indicated that, as expected, students’ perceptions of parental academic support were
positively related to mastery goals while unrelated to performance goals. Also as expected, perceived academic monitoring
was associated with performance goals, although the findings revealed an equal contribution of perceived parental and teacher
involvement. This new insight about the antecedents of students’ achievement goals emphasizes how important is the role of
parental and teacher academic socialization. 相似文献
17.
This study investigated how gender shapes the relationships between classroom environment, achievement goals and maths performance. Seventh-grade students (N?=?498) from five urban secondary schools filled in achievement goal orientations and classroom environment scales at the beginning of the second semester. Maths performance was assessed as an average grade four months later. The results indicated gender differences in the perception of teacher and peers support, achievement goals and maths performance. The effects of goal orientations, teacher and peers support on achievement were moderated by gender. Furthermore, the interaction between classroom environment and performance goals on maths grades varied with gender. In the boys’ sample, performance-avoidance goals interacted with teacher support, while in the girls’ sample, performance-approach goals interacted with peers support in predicting maths grades. The educational implications of these gender differences are discussed. 相似文献
18.
包海玲 《廊坊师范学院学报(自然科学版)》2014,(3):76-79
在众多煤矿的深埋巷道支护中,锚杆破断甚至支护体系失效等问题日渐突出.以淮北临涣矿为工程背景,综合考虑影响深部巷道围岩变形的各种因素,建立了临涣煤矿的深部巷道计算模型.采用大型有限元软件ANSYS,分析软岩影响下的巷道变形特点.分析了锚杆支护下的巷道围岩变形的控制,并结合巷道应力破坏特点,对临涣煤矿锚杆支护进行了支护优化设计.对各种锚杆支护工况进行了数值模拟仿真分析,得出锚杆支护效果不仅与围岩条件及巷道自身特点有关,而且与锚杆自身设计参数有关的结论. 相似文献
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20.
Lucie Hernandez Nathalie Oubrayrie-Roussel Yves Prêteur 《European Journal of Psychology of Education - EJPE》2016,31(2):193-207
Perceived social support has been widely recognized as having beneficial effects on a person’s development, and adolescence is no exception. The objective of this article is to go beyond this “stereotypical” vision of friendship by showing that social support does not always have a positive and direct effect on adolescents’ academic achievement. We sought to understand whether this relationship is mediated by the educational goals and motives that student value and pursue. If these values do not coincide with the expectations and values that the academic institution seeks to transmit, the influence of social support can become harmful, especially with regard to the students’ academic achievement. Data were collected by means of questionnaires from 676 junior high school students in 9th grade from contrasting academic institutions. We chose to observe each participant’s subjective point of view of three dimensions: social support, academic achievement, and educational goals and motives. The results showed that the relationship between social support and attention and involvement in class was negative and mediated by students’ goals. The adolescents with a high level of social support mainly pursued social goals and neglected achievement and future goals. Consequently, these students were less attentive and involved in class. The results also showed that social support was predictive of students’ investment and interest in personal work and success, but only when the students pursued achievement and future goals. 相似文献