浅谈软岩浅埋隧洞工程设计

软岩浅埋隧洞是一种复杂地质条件下的隧洞，对于这类隧洞需要采用适合其特点的设计施工技术。本文以深圳市某排洪隧洞工程为例，详细介绍了采用“新奥法”进行这类隧洞设计的过程，希望能为类似工程地质条件下的隧洞设计提供有益的借鉴。     

隧洞大变形洞段塌方处理

隧洞开挖后破坏了围岩原有的应力平衡,为达到新的平衡,围岩应力必然会重分布,本文就广西某隧洞工程隧洞大变形洞段的塌方处理为例,介绍隧洞大变形洞段灌浆固结法处理变形的一种成功措施。     

论埋藏深度对隧洞围岩与衬砌应力的影响

隧洞开挖引起的围岩应力重新分布和应力集中是导致围岩失稳破坏的根本作用力。在理论分析的基础上,以圆形隧洞为研究对象,应用FLAC3D程序进行数值模拟,分析了埋藏深度对隧洞围岩与衬砌应力的影响规律,为隧洞建设与维护提供科学的理论指导。     

长距离小断面隧道贯通测量的施测方法

本文通过对金川集团三矿区地表排洪工程大白儿泉隧洞的贯通测量,详细介绍了小断面、长距离隧洞贯通测量的误差预计以及施测方法,保证了隧洞的顺利贯通。     

四川某锰矿区引水隧洞泥石流淤塞体水下爆破

泥石流将引水隧洞淤塞后,常规的机械或人工疏通方法不能满足需要。需要降低隧洞内过水水位后,再使用机械施工完成引水隧洞疏通。在此情况下,只有采用水下爆破分散小药包拉槽爆破的方式将淤塞块体解小,并抛掷至洞体两侧形成水槽。此次爆破有效地控制了爆破块度,并保证了引水隧洞的安全,为过水隧洞水下裸露药包爆破成槽施工提供了参考。     

栗西尾矿库排洪洞渗漏原因及治理

通过现场调研、水量观测、取样分析和物探,查清了栗西尾矿库排洪隧洞渗漏的主要原因是库水与排洪隧洞地下水之间有较强的水力联系,造成库水通过断层、节理裂隙等渗漏通道补给隧洞地下水;在对排洪洞不同洞段进行安全分析的基础上,提出了综合治理方案,确保隧洞安全.     

矿区复杂地质条件下隧洞围岩塌方处理

主要介绍金堆城东川河改道工程隧洞施工过程中出现的一次较大塌方治理，塌方体松散并含孤石，传统方法无法处理，根据塌方体的特点，有针对性地采取自钻式锚杆、固结灌浆等施工工艺，并获得成功；对隧洞衬砌、地表陷坑进行了处理，确保了工程安全、质量。同时根据矿区隧洞围岩复杂多变的特点，对后期隧洞施工提出了建议。     

程潮铁矿截排洪隧洞支护优化研究

结合武钢程潮铁矿矿区截排洪续建工程,运用岩土数值分析软件对各类围岩条件下隧洞开挖及支护结构进行数值模拟。并确定隧洞合理的开挖与最优的支护方案。在保证隧洞安全的前提条件下,合理地进行支护设计与施工,尽量节约工程造价和工程投资,保证截排洪工程尽早完成。     

某尾矿库排洪隧洞贯通误差预计方案探讨

该排洪隧洞是整个库区较为重要的防洪排水措施工程,工程成型质量有较高要求,有必要对该隧洞两对头掘进端进行统一系统的高精度测量.在正式的测量工作开始前,根据工程设计图纸编制贯通误差预计方案,方案首先对隧洞内外预布置测量控制点,然后以《工程测量规范GB50026—2007》为依据,达成贯通误差允许值为目标,选取并计算测量精度...     

无衬砌水工压力隧洞围岩破坏机理研究

基于Kiersch导出的在连续、均质和各向同性岩体中开挖圆形隧洞平面问题应力解以及Mohr-Cou-lomn屈服准则,分别研究了圆形有压输水隧洞在施工期和运行期围岩的破坏规律,并根据不同侧压系数,分别推导出了各种情况下洞室围岩的破坏规律,得到了不同侧压系数条件下洞室围岩产生塑性变形的临界内水压力,可以有效地预防无衬砌洞室渗漏水问题,为水工无衬砌有压输水隧洞的设计提供参考。     

Study of Methods to Control Frost Action in Cold Regions Tunnels

This paper presents a case history study of a tunnel in the cold plateau region of China. It describes the permafrost distribution of the mountain in which the tunnel is located and the observed air and surrounding rock temperatures in and outside the tunnel. By comparing these measured temperatures, it is found that the effect of the thermal insulation doors, installed at both ends of the tunnel, raises the air temperature in the tunnel higher than the antisnow shelter installed at both ends of the tunnel. The thermal insulation doors are thought to be better than the antisnow shelters in preventing the tunnel from being damaged by frost action.     

大跨度软弱围岩公路隧道施工过程仿真

横龙山隧道喇叭口段地质条件差，隧道跨度大，给施工带来很大的难度，本文应用有限元方法对大跨度隧道的完整的开挖过程进行了动态模拟研究，模拟开挖采用的双侧壁导坑法的施工全过程，对隧道施工引起的围岩和地表沉降进行了分析，根据仿真计算的结果提出了大跨度隧道施工中应该注意的问题及相应的解决措施。     

Spatial learning and hippocampal volume in male deer mice: relations to age, testosterone and adrenal gland weight

Endoscopic carpal tunnel release is a controversial procedure used in the treatment of carpal tunnel syndrome. Although endoscopic carpal tunnel release is associated with less incisional pain and faster recovery time than the open carpal tunnel release, opponents of endoscopic carpal tunnel release suggest that its benefits are outweighed by its higher complication rates from median nerve transection and transient numbness of the fingers. Because of the huge economic and social impact of carpal tunnel syndrome in this country, we performed a cost-effectiveness analysis comparing endoscopic carpal tunnel release and open carpal tunnel release using guidelines established by the Panel on Cost-Effectiveness in Health and Medicine of the U.S. Public Health Service. A decision analytic model was used to measure differences in cost and effectiveness--expressed as quality-adjusted life-years (QALYs)--between endoscopic carpal tunnel release and open carpal tunnel release. The societal perspective was chosen, and probabilities for various outcomes for the two procedures were obtained from published randomized-controlled trials. Cost data were derived from the Medicare Resource-Based Relative Value Units published in the Federal Register. QALYs were obtained from two groups of health care providers using a utility-assessment questionnaire. Using probabilities for various outcomes from the two published randomized-controlled trials comparing endoscopic carpal tunnel release and open carpal tunnel release, we constructed a decision tree to derive both the cost and the QALYs for the two procedures. The incremental cost difference between endoscopic carpal tunnel release and open carpal tunnel release was $46, using Medicare cost and probabilities of various outcomes derived from a study by Brown et al. in 1993. We calculated QALYs for five age groups--25, 35, 45, 55, 65--assuming a life expectancy of 75 years. The marginal effectiveness (QALY of endoscopic carpal tunnel release minus QALY of open carpal tunnel release) ranged from 0.235 QALY for the 25-year-old age group to 0.066 QALY for the 65-year-old age group, giving a cost-effectiveness ratio of $195/QALY and $693/QALY, respectively. When compared with other accepted medical interventions such as breast cancer screening ($4836/QALY) and exercise to prevent coronary heart disease ($13,508/QALY), endoscopic carpal tunnel release seems to be cost-effective. However, our sensitivity analysis indicated that the cost-effectiveness ratio was very sensitive to a major complication such as median nerve injury. For endoscopic carpal tunnel release to be a cost-effective procedure, the incidence of median nerve injury must be one percentage point less for endoscopic carpal tunnel release than for open carpal tunnel release. Based on the data from the randomized-controlled trials, endoscopic carpal tunnel release seems to be a cost-effective procedure; however, before it can be recommended, greater emphasis must be given to the training of surgeons in this new technique, so that major complications such as median nerve injuries can be avoided. In addition, future studies must better define the actual incidence of nerve injuries for both endoscopic carpal tunnel release and open carpal tunnel release in the community setting.     

The effect of femoral tunnel position and graft tensioning technique on posterior laxity of the posterior cruciate ligament-reconstructed knee

We report the effects of femoral tunnel position and graft tensioning technique on posterior laxity of the posterior cruciate ligament-reconstructed knee. An isometric femoral tunnel site was located using a specially designed alignment jig. Additional femoral tunnel positions were located 5 mm proximal and distal to the isometric femoral tunnel. With the graft in the proximal femoral tunnel, graft tension decreased as the knee flexed; with the graft in the distal femoral tunnel, graft tension increased as the knee flexed. When the graft was placed in the isometric femoral tunnel, a nearly isometric graft tension was maintained between 0 degrees and 90 degrees of knee flexion. One technique tested was tensioning the graft at 90 degrees of knee flexion while applying an anterior drawer force of 156 N to the tibia. This technique restored statistically normal posterior stability to the posterior cruciate ligament-deficient knee between 0 degrees and 90 degrees for the distal femoral tunnel position, between 0 degrees and 75 degrees for the isometric tunnel position, and between 0 degrees and 45 degrees for the proximal tunnel position. When the graft was tensioned with the knee in full extension and without the application of an anterior drawer force, posterior translation of the reconstructed knee was significantly different from that of the intact knee between 15 degrees and 90 degrees for all femoral tunnel positions.     

石膏围岩隧道衬砌结构破坏模式及时变可靠度模型

石膏围岩具有很强的膨胀性和腐蚀性,在隧道全寿命周期内均会引起衬砌结构自身强度劣化及受力增加,严重影响隧道二次衬砌结构可靠性.针对石膏围岩膨胀特性和腐蚀性对隧道二次衬砌结构的影响分别建立了二次衬砌结构膨胀破坏模式和腐蚀破坏模式;考虑石膏围岩膨胀性和腐蚀性对隧道衬砌结构的综合影响,建立了石膏围岩隧道二次衬砌结构综合破坏模式;基于结构体功能函数,推导出能够初步考虑围岩膨胀性和腐蚀性的隧道衬砌结构可靠度指标计算公式;并分别建立了三种破坏模式下的时变可靠度分析模型.采用石膏围岩隧道衬砌结构综合破坏模式下的时变可靠度模型对礼让隧道进行了分析,得到其在使用寿命100 a内的可靠度指标变化规律.根据计算结果可以优化石膏围岩隧道衬砌结构的抗腐蚀、抗膨胀和支护结构设计参数,并对石膏围岩隧道使用寿命周期内的合理维护及维修提供依据.研究成果可推广应用于隧道衬砌结构的可靠度研究中.      

城市隧道照明设计探讨

根据近些年的城市隧道工程设计经验,介绍了隧道照明的设计依据、标准及基本要求,分析了城市隧道照明设计的照明标准值、灯具布置、应急照明、照明控制、配线、节能措施等方面内容,并对隧道照明工程设计实例进行了探讨。     

隧道浅埋暗挖法开挖方案的优化分析

采用岩土工程通用软件FLAC3D对隧道全断面法、两台阶法、三台阶法和CRD法等典型的浅埋暗挖施工方法进行二维数值模拟,分析了在不同开挖方法下施工对隧道围岩稳定的影响。文中选取了某一实际隧道工程为研究对象,通过对不同开挖方法的施工模拟计算,对比分析了各种方法的隧道围岩位移、应力分布以及塑性区大小的规律与特点。     

Battery-Joralemon Street Tunnel

The construction of the Battery-Joralemon Street Tunnel is described. Built between 1903 and 1907, it was the first subway tunnel placed in service under the East River between Manhattan and Brooklyn. Both heading-and-bench rock tunneling and pressurized shield soft-soil tunneling techniques were used. Loss of control of the tunneling shield in partially saturated sands caused variations in alignment that made portions of the tunnel nonfunctional. Approximately 3,000 ft of the tunnel had to be reconstructed to enable subway cars to use the tunnel safely. Additionally, due to concerns regarding the stability of the tunnel in the soft soils, piles were installed under the tunnel to bedrock. The project was a crucible for subway contractors and engineers of the Rapid Transit Commission, especially Clifford M. Holland. His experience on the Joralemon Street Tunnel enabled him to efficiently and safely complete four other East River subway tunnels after the Dual System Agreement of March 1913.