基于弹塑性模型的土洞地区管沟坍塌主要原因分析  

Analysis of Main Causes of Pipeline Trench Collapse in Soil Cave Area Based on Elastic-Plastic Model

作　　者：张效铭[1] 谢孟卿[1] 陈澍 高怡然 

机构地区：[1]中国石油天然气管道局第四工程公司,河北廊坊065000 [2]中油管道建设工程有限公司,河北廊坊065000 [3]中国石油集团东南亚管道有限公司,北京100028

出　　处：《石油工程建设》2015年第6期1-6,共6页Petroleum Engineering Construction

摘　　要：以山西煤层气管道一期工程所处地理环境为例,基于坍塌柱模型、弹塑性模型,分别运用有限元法、极限平衡法对输气管道在吕梁地区含水砂土层地质条件下发生管沟坍塌的可能性以及导致管沟坍塌的主要因素进行分析。计算结果表明,管沟坍塌的影响因素主要有管沟上覆土层的重力、真空负压差和地下水的活动等。管沟上覆土层在重力以及真空负压差的影响下,从边坡开始产生塑性区;在土体吸水软化效应逐渐增强的同时,土体塑性区不断向土洞的上方以及外侧扩展;随着土体参数降到一定值,在管沟受力面的上方产生了贯通的塑性区,上覆土层发生失稳。有限元分析结果表明,地面塌陷多发生在降雨期间,表明地下水的活动对地面塌陷也有着非常重要的影响。Taking the geographic environment of the first stage project of Shanxi Coalbed Methane Pipeline as an example and based on the collapse column model and elastic-plastic model, the finite element method and the limit equilibrium method are applied to analyze the collapse possibility of pipeline trench in water-bearing sand layer in Lyeliang region and the main factors leading to the trench collapse. The computation results show that the main factors include overlying soil weight on trench , under-pressure difference and underground water ac- tivity. The overlying soil layer on trench is affected by its weight and under-pressure, then produces elastic zone staring from its side slope~ with the increasing soil softening effect caused by water absorption, the soil elastic zone extends to the upper side and outer side of soil cave; with soil parameter decreasing to certain values, the connective zones on the upper side of the force bearing surface of trench are formed and the overlying soil layer on trench is instable. The finite element analysis indicates that ground surface collapse oc- curs mostly during the period of rainfall, which shows the underwater activity has a very important effect on ground surface collapse.

关 键 词：管沟坍塌 土洞 坍塌柱模型 弹塑性模型 极限平衡法 有限元法 

分 类 号：TE973[石油与天然气工程—石油机械设备]