液压桩锤液压系统

液压桩锤诸多的优点使其被称为有发展前途的桩工机械。为此作者从液压桩锤液压系统的基本回路、油路连接基本原则、液压元件选择等方面对其进行了系统的介绍，并分析了几种典型液压桩锤液压回路的主要特点。     

液压打桩锤的液压回路

本文在比液压打桩锺与柴油打桩特点的基础上,介绍了液压打桩锺的主要结构特点,重点分析了几种较典型液压打桩锤产品的液压原理,并提出开发新型液压打桩锺需解决的主要技术问题。     

液压打桩锤液压系统的参数化设计

根据液压打桩锤系统运动和动力特性的要求，建立了液压打桩锤液压系统的设计方法，并将设计过程程序化，实现了液压打桩锤液压系统的计算机辅助设计。     

新型液压锤油路系统的设计

在分析双作用液压锤和单作用液压锤油路系统基础上，总结双作用液压锤和单作用液压锤特点，设计出既能实现双作用方式下落又能进行单作用方式下落新型液压锤油路系统。     

HHKA型液压锤的系统分析

液压打桩锤作为一种新型打桩机械,以其污染小、结构简单、打桩效率高等优点正逐渐取代传统的柴油打桩锤。HHKA液压锤是由芬兰JUNTAN公司最近开发的一种新型液压锤,具有液压回路简单、打桩力大、适应范围广、可控制性好等特点,广泛应用于桩基础施工工程中。本文主要对其液压原理和电气控制原理进行分析和介绍。     

TZ200双作用液压打桩锤

液压打桩锤是基础设施建设过程中一种重要的桩工机械,本文主要介绍了TZ200双作用液压打桩锤的工作原理和主要结构,阐述了其液压系统和操作系统构成。利用Simulation X仿真系统进行虚拟仿真设计,并进行了相关实验。仿真分析和实验结果表明,TZ200双作用液压打桩锤性能可靠,满足设计要求。     

双缸双作用液压打桩锤液压系统数值仿真

液压打桩锤利用液压能驱动锤体升降，其优点是可根据土质情况及桩材质的强度，合理选择冲击力，此外，液压打桩锤适合打斜桩作业以及水下桩基施工，同时不存在软土起动困难的问题，能适应各种气候下的施工作业。     

双作用液压打桩锤液压回路

本文对双作用液压打桩锤液压回路进行了理论分析，建立了液压回路的数学模型，在计算机上对桩锤加速下打运动进行数字仿真。通过液压系统的动态试验和冲击末速度的测试，验证其理论分析方法的正确性。     

几种典型外墙外保温系统的应用及若干建议

分别针对EPS板薄抹面外保温系统,XPS板外保温系统,硬泡聚氨酯外保温系统的特点及存在的问题进行了分析,提出了外墙外保温系统设计与施工时应注意的事项,以期指导实践。     

ANN and ANFIS performance prediction models for hydraulic impact hammers

Hydraulic impact hammers are mechanical excavators that can be used in tunneling projects economically under geologic conditions suitable for rock breakage by indentation. However, there is relatively less published material in the literature in relation to predicting the performance of that equipment employing rock properties and machine parameters. In tunnel excavation projects, there is often a need for accurate prediction the performance of such machinery. The poor prediction of machine performance can lead to very costly contractual claims. In this study, the application of soft computing methods for data analysis called artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) to predict the net breaking rate of an impact hammer is demonstrated. The prediction capabilities offered by ANN and ANFIS were shown by using field data of obtained from metro tunnel project in Istanbul, Turkey. For this purpose, two prediction models based on ANN and ANFIS were developed and the results obtained from those models were then compared to those of multiple regression-based predictions. Various statistical performance indexes were used to compare the performance of those prediction models. The results suggest that the proposed ANFIS-based prediction model outperforms both ANN model and the classical multiple regression-based prediction model, and thus can be used to produce a more accurate and reliable estimate of impact hammer performance from Schmidt hammer rebound hardness (SHRH) and rock quality designation (RQD) values obtained from the field tests.     

振动压路机典型行走液压系统分析

对几种典型振动压路机的行走液压系统的组成和特点进行了分析，总结了这几种液压系统的共性，以供有关技术人员和使用部门在管理、使用及保养维修时参考。     

液压挖掘机液压系统概述

在简要说明液压系统对挖掘机的重要性后，提出了挖掘机对液压系统的几点性能要求，具体分析液压挖掘机工作循环的4个基本动作以及行走时的复合动作过程液压作用元件互相配合的流量分配和功率分配，进而介绍挖掘机液压回路的基本类型。     

Safe distance to foundations when compacting soil in the channels by hydraulic hammers

Results are presented for experimental studies conducted on models and full-scale foundations to evaluate the influence exerted by the operation of hydraulic hammers on foundation stability during the compaction of soil. Recommendations are given for safe distances to foundation walls when soil is compacted in the foundation channels with allowance for the impact energy of the hydraulic hammer. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 16–20, September–October, 1997.     

WY21A液压挖掘机新型液压系统

介绍了徐工WY21A液压挖掘机液压系统的主要特点，重点介绍了其缓冲回路、双泵恒功率负流量控制、回转优先、阀内合流、斗杆锁定等功能。     

Driven cast-in-situ piles installed using hydraulic hammers: Installation energy transfer and driveability assessment

The ability of hydraulic pile driving hammers to overcome energy losses during freefall enables a greater proportion of the impact energy to be transferred to the pile than is possible with diesel hammers. This percentage, termed the energy transfer ratio, is not routinely measured in practice however, and there is an element of uncertainty regarding appropriate energy transfer ratios to adopt in driveability analyses. In light of such uncertainties, the energy transfer ratios of four- and five-tonne hydraulic hammers were assessed during installation of driven cast-in-situ (DCIS) piles at several sites in the United Kingdom. The piling rigs were fitted with instrumentation enabling the hammer velocity (and hence kinetic energy) at impact to be inferred for each blow during installation, with the corresponding energy transferred to the closed-ended steel installation tube ascertained using a Pile Driving Analyzer. The results of the study showed that energy transfer ratios were strongly dependent on the hammer drop height, with transfer ratios of 90% and above only achievable for drop heights in excess of 50% of the maximum value. Driveability analyses using measured energy transfer ratios from the fieldwork, as well as the traditional method using an assumed energy transfer ratio which is independent of drop height, yielded good agreement with measured driving records at a clean sand site. In contrast, poorer predictions were apparent for both methods at another site, where the coarse-grained strata had higher fines contents and significant layering, with the traditional method (assumed energy transfer ratio) over-predicting the maximum transferred energy and concealing the influence of dynamic soil properties on driveability. The findings of the study would suggest that lower energy transfer ratios may need to be considered in driveability predictions for these pile types (i.e. steel or DCIS piles) if lower drop heights are used during driving.     

WY21A履带式液压挖掘机新型液压系统

履带式液压挖掘机是一种重要的土方机械，广泛应用在建筑工程、道路工程、水利建设、国防工事等土方施工和矿山采掘中。WY21A型履带式液压挖掘机是我公司在WY20系列产品的基础上，通过优化设计开发的全新型产品。     

国外典型国家的燃气定价模式

城市燃气定价处在燃气供应链的下游,燃气到达城门之后,需要通过城市管网分配到最终用户,最终用户价格=门站价 城市管网的运营成本 固定回报率。有些大的工业用户直接从管道公司批发燃气,有专门的管线,不通过城市管网,而居民用户必须通过城市管网送配,必须补偿城市管网的运营成本。