解析列车冒进信号或越过警冲标事故构成条件

列车冒进信号或越过警冲标事故的构成条件在《铁路交通事故调查处理规则》中有明确规定,但是在分析某一具体情况是否构成本项事故时,还需要紧扣《铁路技术管理规程》,以相关条文为依据,才能准确定性。     

复合锚杆桩在大跨地下通道穿越桥桩中的应用

北京CBD地区银泰-航华地下过街通道主通道(以下简称主通道)穿越既有国贸桥南段,主通道的施工不可避免地会对邻近既有桥梁桩基产生扰动.为保证既有桥梁结构的正常使用和结构安全,对影响范围的国贸桥桩采取复合锚杆桩的保护措施,从而严格控制主通道施工引起桥梁结构的附加沉降.通过计算分析主通道的施工对既有国贸桥桥桩的影响,并结合主通道施工的实际监测资料,表明采用复合锚杆桩加固国贸桥桩基的措施是安全可靠的.     

北京地铁同期在建新线轨道设计思路

回顾北京地铁轨道技术发展的特点,对北京地铁轨道工程进行分析和小结。通过提高标准化设计程度,对各条线的工程特点、难点进行专项分析,思考又好又快地进行北京地铁同期在建新线的轨道设计。总体思路是：轨道工程设计要提高标准化设计的程度,针对各条线工程的特点、难点进行专项创新,展开精细化设计,配合做好工程实施、验收及后评估的全过程,以及推进减振轨道产品研发的系列化与规范化等。     

Initial pre-stress finding and structural behaviors analysis of cable net based on linear adjustment theory

The tensile cable-strut structure is a self-equilibrate pre-stressed system. The initial pre-stress calculation is the fundamental structural analysis. A new numerical procedure was developed. The force density method is the cornerstone of analytical formula, and then introduced into linear adjustment theory;the least square least norm solution, the optimized initial pre-stress, is yielded. The initial pre-stress and structural performances of a particular single-layer saddle-shaped cable-net structure were analyzed with the developed method, which is proved to be efficient and correct. The modal analyses were performed with respect to various pre-stress levels. Finally, the structural performances were investigated comprehensively.     

绵阳机场强夯影响深度及有效加固深度研究

通过绵阳南郊机场强夯加固处理机理的分析,提出了卵砾石填筑地基强夯影响深度及有效加固深度的经验计算公式。研究结果表明:强夯法适用于处理卵砾石填土地基,所提出的经验公式计算卵砾石土层的强夯有效加固深度具有很好的适用性。     

Prospective randomized trial of surgery combined with preoperative and postoperative radiotherapy for rectal carcinoma

Objective To assess the effect of surgery combined with preoperative and postoperative radiotherapy ("sandwich" treatment) in rectal carcinoma. Methods From October 1990 to January 2002, 260 patients with stage Ⅱ (117 patients) and stage Ⅲ (143 patients) rectal carcinoma were randomly divided into three groups: "sandwich" group (92 patients, group A), postoperative radiotherapy group (98 patients, Group B) and operation group (70 patients, Group C). The preoperative accelerated hyperfractionation (15 Gy/6f/3d) was given for "sandwich" group which was followed by conventional postoperative fractionation (DT 35 - 40 Gy/3.5 - 4 weeks). Patients in Group B were given postoperative radiotherapy (Dr 50 Gy/5 weeks). Patients treated with surgery alone served as control. Results The local recurrence rates of Group A, B and C were 5.4% (5/92), 16.3% (16/98) and 64.3% (45/70), respectively (X2 =5.726, P=0.017); and the distant metastasis rates were 6.5% (6/92), 28. 6%(28/98) and 31.4%(22/70), respectively (X2 =15. 703, P= 0. 001). The 3-ycar survival rate was 86. 9%(80/92), 62.2%(61/98) and 51.4%(36/70), respectively (X2 =15. 141, P=0. 001). The 5-year survival rate was 68. 5%(63/92), 54.1%(54/98)and 41.4%(29/70), respectively (X2 =4. 218, P=0.04). The Ⅰ and Ⅱ grades of radiation entero-colitis in Group A and Group B were 7.6% (7/92) and 6.1% (6/98), respectively (X2 = 0. 164, P= 0. 685). Conclusion Surgery combined with preoperative and postoperative radiotherapy can improve the survival rate and reduce the local recurrence rate in rectal carcinoma patients with stage Duke's B (Ⅱ) and C (Ⅲ).     

磁浮车辆运行平稳性的虚拟激励分析方法

为方便、快速地分析多点输入轨道车辆的平稳性,基于虚拟激励原理,提出了平稳性分析方法。当车辆系统受多点全相关随机激励时,应用此方法将多输入多输出系统的响应功率谱矩阵的计算化简为两个矢量相乘,利用所获得的功率谱和随机振动中的反演技术,分析轨道车辆的平稳性指标。以TR08磁浮车辆为原型,建立了磁浮车辆的垂向动力学模型,运用虚拟激励分析方法计算了磁浮车辆的响应功率谱。在频域中,磁浮车辆车体中心处的Sperling指标为1.653,车辆的平稳性等级为优,通过反演运算获得了响应的幅值谱和时间历程,分析过程简单,计算结果准确。     

复杂地质中盾构掘进控制技术探讨

文章结合广州地铁三号线和五号线部分标段的施工实践经验,对不同地质条件下盾构控制技术进行了探讨,剖析了一些常见故障产生的原因,提出了解决对策和预防措施.